Johnson Origins of Equivalent Circuits Origins of the Equivalent Circuit Concept The Voltag

2. Voltmeter 电压表 伏特计3. Ohmmeter 欧姆计 电阻表4. Megohmmeter 兆欧表5. Wattmeter 瓦特计 电表 功率6. Watt-hour 瓦时 瓦特小时7. Ammeter 安培计 电流表8. calibrate 校正9. scale 刻度 量程10. rated 额定的11. interfere with 有害于。

12. indicating needle仪表 指针13. hazardous 危险的14. pivot 支点15. terminal 端子16. spiral 螺旋形的17. spring 弹簧18. shunt 分流，分路，并联，旁路19. rectifier 整流器20. electrodynamometer 电测力计21. strive for 争取22. vane 机器的叶，叶片23. strip 条，带，（跨接）片24. crude 不精细的，粗略的25. polarity 极性26. fuse 保险丝 ，熔丝27. rugged 坚固的28. depict 描绘 ，描写29. cartridge 盒式保险丝30. blow （保险丝）烧断31. plug fuse 插头式保险丝32. malfunction 故障33. deenergize 不给… 通电34. insulation 绝缘35. generator 发电机36. magneto 磁发电机37. humidity 湿度38. moisture 潮湿 湿气39. abbreviate 缩写，缩写为40. transformer 变压器41. thumb 检查 ，查阅42. milliammeter 毫安表43. multimeter 万用表44. dynamometer 测力计，功率计45. aluminum 铝46. deteriorate 使….恶化47. eddy current 涡流48. gear 齿轮 ，传动装置49. dial 刻度盘50. semiconductor 半导体51. squirrel 鼠笼式52. diode 二极管53. thyristor 晶闸管54. transistor 电子晶体管55. triac 双向可控硅56. phase 相位（控制）57. silicon 硅58. crystal 晶体59. wafer 薄片60. anode 阳极 ，正极61. cathode 阴极62. collector 集电极】63. emitter 发射极64. schematic （电路）原理图符号65. leakage 漏电流66. rating 额定值，标称值，定额67. dissipate 散发68. breakdown 击穿69. heat sink 散热器70. self-latching 自锁71. commutation 换向72. geometry 几何结构73. squeeze 压榨，挤，挤榨74. light-dimmer 调光75. capability 容量76. studmounted 拴接式77. hockey puck 冰球78. fin 飞边79. active 有源的80. horsepower 马力81. diameter 直径82. in. （inch ,inches）英寸83. extruded 型材的84. clamp 夹住，夹紧85. compound 紧密 结合86. wrench 扳手87. torque 转矩，扭矩88. enclosure 外（机）壳89. ventilation 通风，流通空气90. sealed-off 封的91. thermal 热的，热量的92. substantially 主要地，实质上地93. aptly 适当地，适宜地94. demystify 阐明95. allude 暗指，直接提到96. cease 停止，终了97. line 线电压98. ripple 脉动.99. redundant 多余的100. separately 单独励磁地101. synchronous 同步电动机102. circuitry 电路，线路103. cost-effective 花费大的104. capacitor 电容器105. dictate 确定106. trade-off 权衡，折衷107. criteria 标准，判据108. analog electronics电力电子学109. saturate 使…饱和110. active region 动态区域111. due 应得到的112. ratio 比，比率113. signify 表示114. encode 编码115. resonance 共鸣116. radiated 传播117. molecule 分子118. diaphragm 震动膜119. acoustic wave 声波120. wavy groove 起伏的沟槽121. deflection 挠度 ，挠曲122. strain gage 应变计量器123. tachometer 转速计124. thermocouple 热电偶125. oscilloscope 示波器126. analytical 解析的127. numerical 数值的128. integrate 求…的积分129. scale 改变比例130. frequency- domain 频域131. random 随机的132. audio 音频的133. operation amplifier 运算放大器134. summation 求和，加法135. sophisticated 复杂的，完善的136. mass-produce 大量生产137. subtract 减去138. inverting amplifier 反向放大器139. uninverting amplifer 同相放大器140. derive 推倒141. active filter 有源滤波器142. stabilize 使稳定143. moderate 适度的，适中的144. virtue 优点145. amplification 扩大146. capacitor 电容器147. impedance 阻抗148. bode plot 波特图149. simulate 模拟，方针150. narrowband filter 带通滤波器151. low-pass filter低通滤波器152. high-pass filter高通滤波器153. differential equation 微分方程154. prebias 预偏置155. summer 加法器156. weighted 加权的157. refinement 改进158. accommodate 适应159. envision 预见160. alphabet 字母表161. validity 正确性162. proposition 命题163. binary 二进制164. nevertheless 然而165. reveal 展现166. complement 补码167. truthtable 真值表168. algebraical 代数的169. trial and error 试错法，试凑法170. elapse 时间（流逝）171. enumerate 列举172. expire 期满,终止173. brute 僵化的174. prime 上撇号175. trigger 引起 ,触发176. inversion 反相 ,反转177. quadruple 四合一178. fabricate 制造179. integrated circuit 集成电路180. capsule 封装181. compatible 兼容的182. obsolete 废弃的183. threshold 门限,阈值184. zener diode 齐纳二极管185. adjacent 临近的,接近的186. arc welding 电弧焊187. intimately 密切地188. recast 重做189. bistable circuit 双稳电路190. cutoff 截止,关闭191. symmetry 对称192. lable 为……标号193. equilibria 平衡194. lever 杆,杠杆195. latch circuit 锁存电路196. depress 压下197. flip-flop 触发器198. glitch 同步199. leading edge 上升沿200. lagging(trailing) edge 下降沿201. inhibit 禁止202. hitherto 迄今,至今203. toggle (来回)切换204. impulse 推动力205. air gap 气隙206. aircraft 飞机207. alternating current, AC 交流208. armature 电枢209. automobile 汽车210. bearing 轴承211. brush 电刷212. carbon 碳213. circumference 圆周214. clearance 间隙215. coils 线圈 绕组216. commutator 换向器217. connection 接线端218. copper bar 铜导条219. copper end rings 铜端环220. core 铁心221. cylindrical 圆柱式的222. doubly excited 双边励磁223. electromechanical 机电的224. felt 毡 225. ferromagnetic 铁磁的226. field pole 磁极227. flux density 磁通密度228. frame 机座，机壳229. generator 发电机230. glue 胶合，粘贴231. graphite 石墨232. induction motor感应电动机233. laminate 叠制，叠压234. lubricant 润滑剂 ，润滑油235. magnetic flux 磁通236.magnetizing current磁化电流，励磁电流237. mechanical rectifier 机械式换向器238. metallic 金属的239. penetrate 透过，渗透240. periphery 周围，圆周241. perpendicular 垂直的，正交的242. polarity 极性243. protrude 使伸出，突出244. reluctance 磁阻245. revolving magnetic field 旋转磁场246. rotor 转子247. salient 突出的248. salient-pole 凸极式249. servo 伺服250. singly excited 单边励磁251. slip rings 滑环252. slot 槽，开槽253. squirrel-cage 鼠笼式，笼型254. stator 定子255. synchronous machine 同步电机256. torque 转矩257. toroid 环状物258. transformer 变压器259. unidirectional 单方向的，方向不变的260. winding 绕组261. wound-rotor 绕线式262. wrap 捆，缠，环绕263. yoke 轭264. allowable temperature rise 允许温升265. alnico 铝镍钴合金266. asynchronous machine 异步电机267. automobile starter motor 汽车启动机268. backlash 啮合间隙，齿隙269. centrifugal force 离心力270. ceramic 陶瓷的271. compound-wound 复励272. constraint 强制，约束273. coun-ter emf 反电势274. coun-terpart 对应物275. culminate 达到极值点276. cumulative compound 积复励277. demagnetization退磁，去磁278. denominator 分母279. differential compound 差复励280. dissipate 浪费281. equilibrium level 平均值282. equivalent circuit 等效电路283. figure of merit品质因数，优值284. flicker 闪烁，摇曳285. flux per pole 每极磁通286. friction 摩擦287. in parallel with 并联288. in series with 串联289. in terms of 根据，在……方面290. in the vicinity of 在…附近，在…左右291. indispensable 必需的，必不可少的292. inherent 固有的293. insulation 绝缘294. long-shunt 长复励295. loss 损耗296. magnetization curve 磁化曲线297. merit 优点，长处，指标298. no load 空载299.nonetheless，none the less仍然，依然300. numerator 分子301. overload 过载302. permissible 允许的303. permanent-magnet永磁304. pertinent 有关的305. power flow diagram 功率流程图306. prefix 前缀，把…放在前面307. rated torque 额定转矩308. reaction 电感309. rheostat 变阻器，电阻箱310. series-wound 串励311. shunt-wound 并励312. short-shunt 短复励313. starting current 启动电流314. starting torque 启动转矩315. synchronous speed 同步转速316. theorem 定理317. turns 匝数318. undervoltage 欠电压319.Ward-Leonard system发电机-电动机组系统320. windage 通风321. yield 产生，提供322. adjacent 相邻的，邻近的323. autotransformer自耦变压器324. braking 制动325. cam 凸轮326. chamber 室，腔327. conveyor 传送机328. corrosion 腐蚀329. coun-terclockwise 逆时针330.coun-ter electromotive force，CEMF 反电势331. dashpot relay 油壶式继电器332. diaphragm 膜片，挡板333. drill 钻床 334. elapse 过去，消逝335. enclosure 机壳336. expel 排出，放出337. fasten 固定，连接338. furnace 炉339. fuse 熔断器，保险丝340. general-purpose relay通用继电器341. hydraulic 液压传动342. initiate 引起，促进343. intake 吸入344. knob 旋钮 ，圆形把手345. latching relay 自锁继电器346. lathe 车床347. limit switch 限位开关348. moisture 潮气，湿度349. mount 安装350. octal-base 八脚的351. orifice 孔，注孔352. pedal 踏板，踏蹬353. phase sequence 相序354. piston 活塞355. pivot 轴，支点，旋转中心356. plunger 可动铁心，插棒式铁心357. pneumatic 气动的358. relay 继电器359. single-phase 单相的360. solenoids 螺线管361. solid-state relay 固态继电器362. spring 弹簧363. tap 抽头364. three-phase 三相365. timing relay 延时继电器366. toggle 搬扭，刀闸367. vibration 振动368. absolute encoder 绝对编码器369. accelerometer 加速度测量仪370. actuator 执行机构371.analog-to-digital conversion,ADC模数转换器 372. angular 角的373. auxiliary 辅助的374. as a rule of thumb 根据经验375. bellows 膜盒376. binary-coded decimal,BCD377. calibration 校准，标定，刻度378. cantilever 悬臂379. closed-loop 闭环■380. induction machine 感应式电机381. horseshoe magnet 马蹄形磁铁382. magnetic field 磁场383. eddy current 涡流384. right-hand rule 右手定则385. left-hand rule 左手定则386. slip 转差率387. induction motor 感应电动机388. rotating magnetic field 旋转磁场389. winding 绕组390. stator 定子391. rotor 转子392. induced current 感生电流393. time-phase 时间相位394. exciting voltage 励磁电压395. solt 槽396. lamination 叠片397. laminated core 叠片铁芯398. short-circuiting ring 短路环399. squirrel cage 鼠笼400. rotor core 转子铁芯401. cast-aluminum rotor铸铝转子402. bronze 青铜403. horsepower 马力404. random-wound 散绕405. insulation 绝缘406. ac motor 交流环电动机407. end ring 端环408. alloy 合金409. coil winding 线圈绕组410. form-wound 模绕411. performance characteristic 工作特性412. frequency 频率413. revolutions per minute 转/分414. motoring 电动机驱动415. generating 发电416. per-unit value 标么值417. breakdown torque 极限转矩418. breakaway force 起步阻力419. overhauling 检修420. wind-driven generator 风动发电机421. revolutions per second 转/秒422. number of poles 极数423. speed-torque curve 转速力矩特性曲线424. plugging 反向制动425. synchronous speed 同步转速426. percentage 百分数427. locked-rotor torque 锁定转子转矩428. full-load torque 满载转矩429. prime mover 原动机430. inrush current 涌流431. magnetizing reacance 磁化电抗432. line-to-neutral 线与中性点间的433. staor winding 定子绕组434. leakage reactance 漏磁电抗435. no-load 空载436. full load 满载437. Polyphase 多相(的)438. iron-loss 铁损439. complex impedance 复数阻抗440. rotor resistance 转子电阻441. leakage flux 漏磁通442. locked-rotor 锁定转子443. chopper circuit 斩波电路444. separately excited 他励的445. compounded 复励446. dc motor 直流电动机447. de machine 直流电机448. speed regulation 速度调节449. shunt 并励450. series 串励451. armature circuit 电枢电路452. optical fiber 光纤453. interoffice 局间的454. waveguide 波导 波导管455. bandwidth 带宽456. light emitting diode 发光二极管457. silica 硅石 二氧化硅458. regeneration 再生, 后反馈放大459. coaxial 共轴的,同轴的460. high-performance 高性能的461. carrier 载波462. mature 成熟的463. Single Side Band(SSB) 单边带464. coupling capacitor 结合电容465. propagate 传导 传播466. modulator 调制器467. demodulator 解调器468. line trap 限波器469. shunt 分路器470. Amplitude Modulation(AM调幅471. Frequency Shift Keying(FSK)移频键控472. tuner 调谐器473. attenuate 衰减474. incident 入射的475. two-way configuration 二线制476. generator voltage 发电机电压477. dc generator 直流发电机478. polyphase rectifier 多相整流器479. boost 增压480. time constant 时间常数481. forward transfer function 正向传递函数482. error signal 误差信号483. regulator 调节器484. stabilizing transformer稳定变压器485. time delay 延时486.direct axis transient time constant直轴瞬变时间常数487. time invariant 时不变的488. transient response 瞬态响应489. solid state 固体490. buck 补偿491. operational calculus 算符演算492. gain 增益493. pole 极点494. feedback signal 反馈信号495. dynamic response 动态响应496. voltage control system 电压控制系统497. mismatch 失配498. error detector 误差检测器499. excitation system 励磁系统500. field current 励磁电流501. transistor 晶体管502. high-gain 高增益503. boost-buck 升压去磁504. feedback system 反馈系统505. reactive power 无功功率506. feedback loop 反馈回路507. automatic Voltage regulator(AVR) 自动电压调整器508. third harmonic voltage 三次谐波电压509. reference Voltage 基准电压510. magnetic amplifier 磁放大器511. amplidyne 微场扩流发电机512. self-exciting 自励的513. limiter 限幅器514. manual control 手动控制515. block diagram 方框图516. linear zone 线性区517. potential transformer 电压互感器518. stabilization network 稳定网络519. stabilizer 稳定器520. air-gap flux 气隙磁通521. saturation effect 饱和效应522. saturation curve 饱和曲线523. flux linkage 磁链524. per unit value 标么值525. shunt field 并励磁场526. magnetic circuit 磁路527. load-saturation curve 负载饱和曲线528. air-gap line 气隙磁化线529. polyphase rectifier 多相整流器530. circuit components 电路元件531. circuit parameters 电路参数532. electrical device 电气设备533. electric energy 电能534. primary cell 原生电池535. energy converter 电能转换器536. conductor 导体537. heating appliance 电热器538. direct-current 直流539. self-inductor 自感540. mutual-inductor 互感541. the dielectric 电介质542. storage battery 蓄电池543. e.m.f = electromotive fore电动势544. unidirectional current 单方向性电流545. circuit diagram 电路图546. load characteristic 负载特性547. terminal voltage 端电压548. external characteristic外特性549. conductance 电导550. volt-ampere characteristics伏安特性551. carbon-filament lamp 碳丝灯泡552. ideal source 理想电源553. internal resistance 内阻554.active(passive)circuit elements有（无）源电路元件555. deviation 偏差556. leakage current 漏电流557. circuit branch 支路558. P.D. = potential drop 电压降559. potential distribution 电位分布560.r.m.s values=root mean square values 均方根值561. permanent magnet 永磁体562. effective values 有效值563. steady direct current 恒稳直流电564. sinusoidal time function 正弦时间函数565. complex number 复数566. Cartesian coordinates 笛卡儿坐标系567. modulus 模568. real part 实部569. imaginary part 虚部570. displacement current 位移电流571. trigonometric transformations 瞬时值572. epoch angle 初相角573. phase displacement 相位差574. signal amplifier 小信号放大器575. mid-frequency band 中频带576. bipolar junction transistor(BJT双极性晶体管577. field effect transistor(FET)场效应管578. electrode 电极 电焊条579. polarity 极性580. gain 增益581. isolation 隔离 分离 绝缘 隔振582. emitter 发射管放射器 发射极583. collector 集电极584. base 基极585. self-bias resistor 自偏置电阻586. triangular symbol 三角符号587. phase reversal 反相588. infinite voltage gain 无穷大电压增益589. feedback component 反馈元件590. differentiation 微分591. integration 积分下限592. impedance 阻抗593. fidelity 保真度594.summing circuit总和线路反馈系统中的比较环节595. pneumatic 气动的596. Oscillation 振荡597. inverse 倒数598. admittance 导纳599. transformer 变压器600. turns ratio 变比 匝比601. ampere-turns 安匝(数)602. mutual flux 交互(主)磁通603. vector equation 向(相)量方程604. power frequency 工频605. capacitance effect 电容效应606. induction machine 感应电机607. shunt excited 并励608. series excited 串励609. separately excited 他励610. self excited 自励611. field winding 磁场绕组 励磁绕组612.speed-torque characteristic速度转矩特性613. dynamic-state operation动态运行614. salient poles 凸极615. excited by 励磁616. field coils 励磁线圈617. air-gap flux distribution 气隙磁通分布618. direct axis 直轴619. armature coil 电枢线圈620. rotating commutator 旋转（整流子）换向器mutator-brush combination换向器-电刷总线622. mechanical rectifier 机械式整流器623. armature m.m.f. wave 电枢磁势波624. Geometrical position 几何位置625. magnetic torque 电磁转矩626. spatial waveform 空间波形627. sinusoidal–density wave正弦磁密度628. external armature circuit 电枢外电路629.instantaneous electric power瞬时电功率630.instantaneous mechanical power瞬时机械功率631. effects of saturation 饱和效应632. reluctance 磁阻633. power amplifier 功率放大器634. compound generator 复励发电机635. rheostat 变阻器636. self – excitation process 自励过程637. commutation condition 换向状况638.cumulatively compounded motor积复励电动机639. operating condition 运行状态640. equivalent T – circuit T型等值电路641.rotor(stator)winding转子（定子绕组）642. winding loss 绕组（铜）损耗643. prime motor 原动机644. active component 有功分量645. reactive component 无功分量646. electromagnetic torque 电磁转矩647. retarding torque 制动转矩648.inductive component感性（无功）分量649. abscissa axis 横坐标650. induction generator 感应发电机651. synchronous generator 同步发电机652. automatic station 无人值守电站653. hydropower station 水电站654. process of self – excitation 自励过程655. auxiliary motor 辅助电动机656. technical specifications 技术条件657. voltage across the terminals 端电压658. steady – state condition瞬态 暂态659. reactive in respect to 相对….呈感性660. active in respect to 相对….呈阻性661.synchronous condenser同步进相（调相）机662. coincide in phase with 与….同相663. synchronous reactance 同步电抗664. algebraic 代数的665. algorithmic 算法的666. biphase 双相的667. bilateral circuit 双向电路668. bimotored 双马达的669. corridor 通路670.shunt displacement current旁路位移电流671. leakage 泄漏672. lightning shielding 避雷673. harmonic 谐波的674. insulator string 绝缘子串675. neutral 中性的676. zero sequence current 零序电流677. sinusoidal 正弦的678. square 平方679. corona 电晕,放电680. bypass 旁路681. voltmeter 电压表682. ammeter 电流表683. micrometer 千分尺684. thermometer 温度计685. watt-hour meter 电度表686. wattmeter 电力表687. private line 专用线路688. diameter 直径689. centimeter 厘米690. restriking 电弧再触发691. magnitude 振幅692. oscillation 振荡693. auxiliary 辅助的694. protective gap 保护性间隙放电695. receptacle 插座696. lightning arrester 避雷装置697. bushing 套管698. trigger 起动装置699. stress 应力700. deterioration 损坏,磨损701. spark gap 火花放电隙702. traveling-wave 行波703. wye-connected 星形连接704. enclosure 设备外壳705. live conductor 带电导体706. fuse 熔断器707. structural 结构上的708. out-of-step 不同步的709. resynchronize 再同步710. synchroscops 同步指示器711. automatic oscillograph 自动示波器712. nominally 标称713. sampling 采样714. potential transformer 电压互感器715. fraction 分数716. switchyard 户外配电装置717. hazard 危险718. bushing 高压套719. contact 触点720. energize 励磁721. trip coil 跳闸线圈722. over-current relay 过电流继电器723. armature 衔铁724. pickup current 始动电流725. release current 释放电流726. solenoid relay 螺管式继电器727. induction-disc relay 感应圆盘式继电器728. inverse time relay 反时限继电器729. hydraulic 液力的730. dashpot 阻尼器733. electrical stressing 电气应力734. mechanical stressing 机械应力■735. crystal 晶体的，水晶，晶体736. demodulation 解调737. derivative 导数738. diaphragm 膜片739. differentiation 微分740. discrete 离散的741. displacement 位移742. eddy 涡流743. encoder 编码器744. error 误差，偏差745. expedite 加速746. feedback 反馈747. feedforward 前馈748. forging 锻造749. hysteresis 磁滞750. immunity 抗扰性751. impedance 阻抗752. increment encoder 增量编码器753. inertia 惯性754. integration 积分755. interface 接口756. jerk 振动，冲击757. kinematic 运动的，运动学的758. longitudinal 经度了；纵向的759. manipulations 操作，控制，处理760. manipulator 机械手，操作器761. measurand 被测量，被测量对象762. modulation 调制763. multiplexer 多路转换器764. offset 偏心765. open-loop 开环766. orthogonal 垂直的，正交的767. perpendicular 垂直的，正交的768. photosensor 光电传感器769. piezoelectric 压电的770. plant 装置，设备771. potentiometer 电位器772. predominant 主要的，突出的773. prismatic 棱型的774. proximity 距离775. quantization 量化776. radial 径向的777. redundant 多余的，重复的778. representation 代表，表示779. resolver 解算器780. resonance 共振781. revolute 旋转的，转动的782. rig 设备783. robustness 鲁棒性784. rolling 轧制785. sampling period 采样周期786. signal-to-noise ration ，SNR信噪比787. strategy 策略788. subsequently 其后789. tachometer 测速仪790. terminology 术语，专门名词791. threshold 门，界限，阈值792. trajectory 轨迹793. transducer 传感器794. transient 瞬态的795.transistor-to-transistor logic，TTL晶体管-晶体管逻辑796. transit 运输797. translatory 平移的798. algorithm 算法799. ambiguity 模棱两可800. antenna 天线801. arbitration 仲裁，公断802. autonomous 匿名的803. capacity 容量804. chao 混乱805. checksum 检查和806. circumnavigate 饶过807. client-server 客户-服务器808. client-server model 客户服务器模型809. corridor 通道，走廊810. decouple 解耦，去除干扰811. depict 描述812. distributed system 分布式系统813. dungen 地牢814. electronic mail 电子邮件815. entity 实体816. etiquette 规则817. exponential 指数818. fallout 余波，附带结果819. forward 转发820. full-duplex 全双工821. gamut 全体，整体822. goggles 护目镜，潜水镜823. half-duplex 半双工824. hierarchy 阶梯，等级825. host 主机826. infrastructure 基础，底层结构827. interactive 交互式828. interface data unit 接口数据单元829. inventory 存货，清单830. killer 迷人的831. newsgroup 新闻组832. object-oriented 面向对象的833. outgoing 外出了，离开的834. pointer 指针835. primitive 操作，原型836. process 进程837. propagation 传播，宣传838. protocol 协议839. protocol data unit 协议数据单元840. remote database 远程数据库841. remote login 远程登陆842. remote terminal 终端843. reprisal 报复844. router 路由器845. service data unit 服务数据单元846. simultaneous 同时的847. static allocation 静态分配848. subnet 子网849. taxonomy 分类学，分类850. telemedicine 远程医疗851. terminology 术语852. testbed 测试平台853. therapy 治疗854. token 令牌855. topology 拓扑学856. videoconference 可视会议857. virtual reality 虚拟现实858. worldwide shared 全球共享的859. wide area network 广域网860. actuator 执行器861. bar code reader 条码阅读器862. by-product 副产品863. call for 需要864. contiguous 邻近的865. culprit 犯罪者866. elusive 难以捉摸的867. filter 滤波器868. fluctuation 升降剥动，不规则的变化869. hardwired 硬接线的870. havoc 大破坏871. high-volume 大容量872. induction coupling 感应耦合873. inference 干扰874. injection molding 注模875. instruction set 指令集876. interconnection 相互连接877. isolation transformer 隔离变压器878. maintenance 维护879. multiple axis drive 多轴驱动880. pilot light 信号灯881. RF noise 射频干扰882. shock 冲击883. solenoid 线圈884. stand-alone 独立的885. stepper 步进电机886. thermocouple 热电偶887. troubleshoot 排除故障888.uninterruptible power supply不间断电源889. vendor 生产厂商890. vibration 震动891. water-tight 防水892. wreak 发泄，报复893. configuration 组态894.Cyclic Redundancy Check循环冗余检查895. electromagnetic interference 电磁干扰896. meticulous 详细的897. nonvolatile 非挥发的898. parity 校验899. peripheral 外设900. pharmaceutical 药剂，药品901. rack mounting 机架安装902. resident program 驻留程序903. spare 备用的904. standby 后备的905. volatile 挥发的，易失的906. watchdog timer 看门狗定时器907. distribution 分配，配电908. primary 最初的，基本的，初级线圈909. radial 径向的，辐射状的910. premise 上述各点，前言，根据911. residential 住宅的，居住的912. residence 住宅913. occupancy 占有，占用，居住914. tap 抽头915. establishment 组织，部门916. dwelling 住房917. panel 操纵台，面板918. laundry 洗衣房919. means 手段，工具920. condominium （国际）共官921. branch circuit 直路922. conduit 导线，导线管923. rigid 刚性的，坚固的924. clamp 夹，钳925. bolt 螺栓926. cubicle 立方体927. interrupter 断续(流、电、路)器928. margin 余量，裕度929. nuisance 障碍，公害930. receptacle 插座，插孔931. algebraic 代数的932. virtually 实际上，实质上933. fluorescent 荧光的，有荧光性的934. fixture 设备，装置】935. vicinity 附近，邻近，接近936. ballast 镇流器937. feeder 馈电线，电源线，馈电板938. ground-fault protector （GFP）939.ground-fault circuit interrupter （GFCI）接地故障保护器，接地故障断路器940. centrifugal 离心的，离心力941. whilst=while942. sphere 球体943. coun-teract 抵抗，抵消，消除944. joint 关节，铰链945. keyway 键槽946. pivot 轴，支点947. link 连杆948. throttle 节流阀，风门949. synthesis 综合物950. mass 物质，块，堆951. classic 古典的，经典的，传统的952. steer 驾驶，操纵，引导953. servomechanism 伺服机构，伺服系统954. actuate 激励，驱动955. intimately 紧密地，直接的956. academic 纯理论的957. dial 刻度盘，调节控制盘958. calibration 标定，标准化959. lubrication 润滑，注油960. arrangement 结构961. wear 磨损，损耗962. subtle 微妙的，巧妙的963. transducer 变送器964. hand-wheel 手轮，驾驶盘，操纵盘965. hydraulic 液压的，液压传动装置966. pneumatic 气动的，气动力学的967. electro-hydraulic 电动液压的968. electro-pneumatic 电动气动的969. coincidence 一致，相等970. faithful 正确的，可靠的971. fidelity 重现精度，真实，正确972. oscillatory 振动的，摆动的973. align 调整，校准974. profile 轮廓，仿行975. milling machine 铣床976. gyroscope 陀螺仪977. launcher 发生器，启动装置978. inertial 惯性的，惯量的979. electrolytic 电解的980. plate （电）镀981. distillation 蒸馏982. blend 混合，调和，配料983. philosophy 基本原理984. analytical 分析的，分解的985. orifice 侧流板，隔板986. diaphragm 膜，隔板987. knob 钮，圆形把手988. nomenclature 术语989. liable 有责任的990. autonomic 自治的991. grossly 大概，大体上的992. ideological 思想的993. morally 道德上，道义上994. boredom 讨厌，无趣995. deterioration 变化，降低品质996. ambient 环境的997. remarks 附注，要点998.differential pressure transducer差压变送器999. viscous 粘稠的1000.viscous friction 粘滞摩擦.1001.bearing 轴承1002.rolling mill 轧钢机1003.mine minder 矿坑卷扬机1004.velodyne 伺服积分器1005.feasible 可行的1006.regenerative braking 回馈制动1007.eddy current braking 涡流制动1008.dynamic braking 能耗制动1009.reverse braking 反接制动1010.advent 出现1011.prolong 延长1012.armature 电枢1013.contactor 接触器1014.hoist 起重机1015.field winding 励磁绕组mutator 换向器1017.riiple 纹动1018.creep 蠕动1019.tachogenerator 测速发电机1020.quadrant 象限1021.coast 跟踪惯性1022.profile 轮廓1023.conveyance 运输工具1024.lever 手柄，控制杆1025.forced commutation 强迫换流1026.ac squirrel cage induction motor交流笼型感应电动机1027.accutrol 控制器1028.stator 定子1029.rotor 转子1030.DC link 直流环节1031.Triac 双向晶闸管1032.Adjustable-voltage inverter电压型逆变器1033.Current source inverter 电流型逆变器1034.refinement 明确表达1035.pros and cons 优缺点1036.cogging 齿槽效应.1037.retrofit 改型1038.damper 减速器1039.pitfall 缺陷1040.vernier 游标尺1041.jog 啮合1042.runout table 输出轨道1043.clinker-cooler 熟料冷却器1044.kiln 炉1045.grinder 磨床1046.pitch 齿轮1047.inventory 存货1048.cone pulley 塔轮，快慢轮1049.escalation 升级，提高1050.forced-draft 强制通风1051.induced-draft fan 吸风机1052.elbow 弯头。

近百年对世界影响最大的发明英语作文全文共3篇示例，供读者参考篇1The Most Impactful Inventions of the Last 100 YearsWe're living in an era of unprecedented technological progress. Over just the past century, groundbreaking inventions have transformed our world in unimaginable ways. As a student, I'm in awe of the brilliant minds behind these innovations that have shaped modern society. In this essay, I'll explore what I believe are the most impactful inventions since the 1920s and their profound effects on our daily lives.The first pivotal invention I'd like to discuss is the internet. Although its origins date back to the 1960s, it was the development of the World Wide Web in 1989 by Sir Tim Berners-Lee that truly sparked the internet revolution. This global network has become deeply embedded into the fabric of 21st century life, revolutionizing how we communicate, work, learn, shop, and entertain ourselves.As students, the internet has been an invaluable resource for research and education. We have the entirety of humanknowledge at our fingertips through online libraries and databases. Lessons and lectures can happen virtually, democratizing access to quality education globally. The internet's impact simply cannot be overstated – it has connected our world in unprecedented ways.Next, I'd highlight the immense importance of vaccines and antimicrobial drugs. Life expectancy has skyrocketed since the invention of penicillin in 1928 and the subsequent development of antibiotics, antivirals, and vaccines that can prevent and treat infectious diseases. Epidemics that once devastated populations can now be controlled. As a direct result of vaccines, smallpox was declared eradicated in 1980 by the World Health Organization.As students, we've been protected by a host of routine immunizations that allow us to learn and grow up healthy. Without these extraordinary medical inventions, schools would face constant outbreaks of measles, polio, and other illnesses. The ability to treat bacterial and viral infections has transformed public health beyond recognition compared to a century ago.Another epochal breakthrough is the invention of nuclear technology, both for energy generation and arguably as the most destructive weapon ever created. The first controllednuclear fission chain reaction in 1942 changed the course of modern history, ushering in the nuclear age. While nuclear power has been controversial, it provides a tremendous amount of the world's electricity today through fission reactors.On the other hand, the creation of nuclear weapons has had a chilling effect on geopolitics. Their sheer destructive capability represents a threat to all humanity. As students, we've grown up in the long shadow and deterrence of nuclear armaments during the Cold War era. Now, the quest for harnessing safe, controlled nuclear fusion could be an amazing source of virtually limitless clean energy for our planet's future.It's hard to overstate the significance of the semiconductor and microchip, which has driven the digital revolution and rise of modern computing. While the first transistors and integrated circuits emerged in the 1950s-60s, their relentless miniaturization following Moore's Law predictions enabled increasingly powerful and compact electronic devices year after year.From basic calculators to supercomputers, microchips have enabled the Information Age we live in. As students, we use chipsets to power our laptops, smartphones, gaming consoles, and a myriad of digital technologies that make modern lifepossible. Shrinking transistors into microprocessors has vastly increased computing performance, efficiency, and capabilities. The semiconductor is the foundation and core driving force of the digital world.In the realm of communications, we've witnessed incredible growth from the earliest telephone networks to modern mobile phones and data transmission. The first practical cell phone system was prototyped in 1973, followed by commercial mobile services in the 1980s. This wireless technology untethered voice and data communications from landlines.Today, smartphones combine advances in computing, cameras, networking and more into powerful handheld computers that most students have constant access to. We videoconference, stream media, get turn-by-turn directions, and have near-infinite information just a tap away. Cellular networks and data transmission protocols like WiFi, Bluetooth, and 5G have enabled ubiquitous digital connectivity that has reshaped society.More recent but no less impactful inventions have emerged in the fields of renewable energy. The commercial development of photovoltaic solar cells and wind turbines has allowed humanity to harness clean electricity from the power of the sunand atmosphere. As the threat of climate change looms, these technologies represent crucial innovations as the world transitions to sustainable energy sources over fossil fuels.As students looking towards the future, renewable energy gives me hope that we can power our growing energy needs in a way that doesn't exacerbate the global climate crisis. Whether through improvements in solar panel efficiency, battery storage, offshore wind farming, or other advances, green energy inventions will play a vital role.Of course, many other inventions have transformed our modern world, from airplanes to plastics, televisions, GPS, the birth control pill, and more. But in my analysis, the inventions I've highlighted stand out as having an extraordinary impact that has shaped the era we live in as 21st century students.Looking back over the past 100 years of breathtaking innovation, I'm awestruck by the creativity, perseverance and brilliance of the human minds behind these world-changing breakthroughs. To imagine what wonders may emerge in the next century fills me with a sense of excitement and hope for the future we'll inherit as the next generation.As a student today, it's easy to take the remarkable technologies all around me for granted. But by understandingthe immense impact of inventions like the internet, vaccines, nuclear power, semiconductors, cellular networks, and renewable energy systems, I gain a deeper appreciation for how rapidly our modern world has advanced thanks to the brightest scientists and innovators throughout the 20th century and into the 21st.While we've seen profound disruptions and transformations from these inventions, they've often provided solutions to humanity's greatest challenges while opening up new realms of possibility. Despite the risks of powerful new technologies, that drive for incremental progress is part of the grand human experiment that has launched us from the age of the telegraph to interplanetary probes streaking through the cosmos.I feel tremendously fortunate to be a student experiencing the world made possible by a century's worth of groundbreaking inventions. At the same time, I'm inspired and motivated by these wonders of human ingenuity to keep learning, creating, and someday contributing innovations of my own for the betterment of the world we all share.篇2The Most Impactful Inventions of the Past 100 YearsAs a student living in the 21st century, I am constantly in awe of the rapid technological advancements that have shaped our modern world. It's mind-boggling to think about how different life was just a century ago, before many of the inventions we now take for granted were even conceived. In this essay, I will explore some of the most impactful inventions of the past 100 years and discuss how they have revolutionized various aspects of our lives.One of the inventions that has had a profound impact on society is the internet. Developed in the 1960s as a communication network for the U.S. military, the internet has since evolved into a vast global network that has transformed the way we communicate, access information, and conduct business. The advent of the World Wide Web in the 1990s made the internet accessible to the general public, and today, it is an integral part of our daily lives. From online shopping and banking to social media and remote work, the internet has reshaped nearly every aspect of modern society.Another game-changing invention is the smartphone. While mobile phones have been around since the 1970s, the introduction of smartphones in the early 2000s revolutionized the way we interact with technology. These pocket-sized devices have evolved into powerful computing devices that allow us toaccess the internet, take photos, navigate with GPS, and perform a myriad of other tasks on the go. Smartphones have become an indispensable tool for communication, productivity, and entertainment, and their impact on our lives is undeniable.In the field of medicine, one of the most significant inventions of the past century is the development of antibiotics. Prior to the discovery of penicillin in 1928 by Alexander Fleming, bacterial infections were often fatal, and even minor injuries could lead to life-threatening complications. The advent of antibiotics has saved millions of lives and has significantly improved our ability to treat and prevent a wide range of infectious diseases.The invention of the airplane has also had a profound impact on our world. While the Wright brothers achieved the first powered flight in 1903, it wasn't until the mid-20th century that air travel became widely accessible. Today, airplanes have revolutionized transportation, allowing us to travel vast distances in a matter of hours and facilitating the global exchange of goods, services, and ideas.In the realm of energy, the development of nuclear power has been both a significant achievement and a source of controversy. The first nuclear reactor was built in 1942, and thefirst nuclear power plant went online in 1954. While nuclear power has provided a source of clean and efficient energy, concerns over safety and the disposal of radioactive waste have sparked ongoing debates about its long-term viability.Another invention that has had a profound impact on our lives is the birth control pill. Introduced in the 1960s, the pill revolutionized family planning and gave women unprecedented control over their reproductive lives. This invention has played a significant role in advancing women's rights and empowerment, allowing women to pursue education and careers without the constant fear of unplanned pregnancies.In the field of electronics, the invention of the transistor in 1947 paved the way for the development of modern computers and countless other electronic devices. Transistors, which are small electronic switches, replaced bulky and inefficient vacuum tubes and enabled the miniaturization of electronics. Without the transistor, many of the technological advancements we enjoy today would not have been possible.As we look to the future, it's exciting to imagine the revolutionary inventions that lie ahead. Perhaps we will witness the development of practical quantum computers, which could solve complex problems at an unprecedented speed. Or maybewe will see the widespread adoption of renewable energy sources, such as solar and wind power, helping to mitigate the effects of climate change.In conclusion, the past 100 years have been a period of remarkable innovation, with inventions that have transformed virtually every aspect of our lives. From the internet and smartphones to antibiotics and air travel, these inventions have reshaped our world in ways that would have been unimaginable to our ancestors. As students living in this era of rapid technological change, it's crucial that we appreciate the significance of these inventions and strive to build upon them, creating new innovations that will shape the world for generations to come.篇3The Greatest Innovations That Shaped Our WorldOver the past century, human ingenuity and relentless pursuit of progress have given rise to remarkable inventions that have transformed our world in profound ways. As a student witnessing the marvels of modern technology, I am in awe of the revolutionary advancements that have reshaped our lives, pushing the boundaries of what was once deemed impossible.One invention that stands out as a true game-changer is the internet. Born from the humble beginnings of interconnected computer networks, the internet has evolved into a vast digital realm that has redefined communication, knowledge sharing, and global connectivity. With just a few clicks, we can access a wealth of information, connect with individuals across the globe, and immerse ourselves in virtual worlds that blur the lines between reality and the digital realm. The internet has disrupted traditional industries, given rise to new business models, and democratized access to knowledge like never before.Another groundbreaking invention that has left an indelible mark on our lives is the smartphone. This sleek, pocket-sized device has revolutionized how we communicate, navigate, and interact with the world around us. Smartphones have become our constant companions, providing us with instant access to information, entertainment, and social connections. They have transformed the way we capture and share moments, enabling us to document our lives in real-time and connect with others in ways that were once unimaginable.The field of medicine has also witnessed remarkable advancements, thanks to innovative technologies like medical imaging and bioengineering. Devices such as MRI scanners, CTscans, and genetic sequencing have opened new frontiers in diagnosing and treating diseases, paving the way for personalized medicine and targeted therapies. Prosthetic limbs and implantable devices have restored mobility and quality of life for countless individuals, pushing the boundaries of what was once considered science fiction.However, innovations are not solely confined to the realm of technology. Social and cultural movements have also left an indelible mark on our world. The fight for civil rights, gender equality, and LGBTQ+ rights has reshaped societal norms, challenging long-held prejudices and paving the way for a more inclusive and equitable society. These movements have sparked crucial conversations, ignited social change, and challenged us to confront our biases, reminding us that progress is not solely measured in technological advancements but also in our collective evolution towards empathy and understanding.As we look to the future, the pace of innovation shows no signs of slowing down. Emerging technologies like artificial intelligence, quantum computing, and renewable energy sources promise to revolutionize industries, tackle global challenges, and unlock new realms of possibility. However, with theseadvancements come ethical considerations and responsibilities that we must navigate with wisdom and foresight.In conclusion, the past century has witnessed a remarkable tapestry of inventions and innovations that have profoundly shaped our world. From the internet and smartphones to medical breakthroughs and social movements, these advancements have not only transformed our daily lives but have also challenged our perceptions of what is possible. As students of this rapidly evolving world, it is our duty to embrace these innovations with curiosity and critical thinking, while also recognizing the ethical implications and responsibilities that accompany such transformative power. Only by striking a delicate balance between technological progress and ethical considerations can we truly harness the potential of these inventions to create a better world for ourselves and future generations.。

第二章67页2.1.1The essential structure of a BJT is represented in Figure 2-1(a).双极性晶体管的基本结构如图2-1（a）所示。

The very earliest such devices had structures literally of this kind.早期器件就具有上面所说的这种的结构。

Two closely spaced junctions were created by crystal-growth methods, and a “bar” or parallelepiped was then cut out of the germanium crystal.两个紧密间隔开的结是由晶体生长方法产生，和一个“杆”或平行六面体，然后切出锗晶体。

Electrical leads were attached to it (an enormous challenge!) and the result was a BJT. For reasons that will be explained shortly, these electrical terminals are given the names, respectively from left to right, emitter, base, and conductor.导线被连接到结（一个巨大的挑战！），结果是一个BJT（双极性晶体管）。

将要简短解释的原因，这些电气端子被赋予名称，分别由左到右，发射极，基极，和集电极。

These names were chosen with an eye to distinctive initial letters, which are displayed in Figure 2-1(a) in association with the three terminals.这三个极用三个独特的字母表示（E、B、C），如图2-1（a）所示。

Inverter1 IntroductionAn inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits.Solid-state inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.There are two main types of inverter. The output of a modified sine wave inverter is similar to a square wave output except that the output goes to zero volts for a time before switching positive or negative. It is simple and low cost and is compatible with most electronic devices, except for sensitive or specialized equipment, for example certain laser printers. A pure sine wave inverter produces a nearly perfect sine wave output (<3% total harmonic distortion) that is essentially the same as utility-supplied grid power. Thus it is compatible with all AC electronic devices. This is the type used in grid-tie inverters. Its design is more complex, and costs 5 or 10 times more per unit power The electrical inverter is a high-power electronic oscillator. It is so named because early mechanical AC to DC converters were made to work in reverse, and thus were "inverted", to convert DC to AC.The inverter performs the opposite function of a rectifier.2 Applications2.1 DC power source utilizationAn inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltageGrid tie inverters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch off automatically in the event of a blackout.Micro-inverters convert direct current from individual solar panels into alternating current for the electric grid. They are grid tie designs by default.2.2 Uninterruptible power suppliesAn uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier supplies DC power to recharge the batteries.2.3 Induction heatingInverters convert low frequency main AC power to a higher frequency for use in induction heating. To do this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power.2.4 HVDC power transmissionWith HVDC power transmission, AC power is rectified and high voltage DC power is transmitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC.2.5 Variable-frequency drivesA variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.2.6 Electric vehicle drivesAdjustable speed motor control inverters are currently used to power the traction motors in some electric and diesel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles such as the Toyota Prius and Fisker Karma. Various improvements in inverter technology are being developed specifically for electric vehicle applications.[2] In vehicles with regenerative braking, the inverter also takes power from the motor (now acting as a generator) and stores it in the batteries.2.7 The general caseA transformer allows AC power to be converted to any desired voltage, but at the same frequency. Inverters, plus rectifiers for DC, can be designed to convert from any voltage, AC or DC, to any other voltage, also AC or DC, at any desired frequency. The output power can never exceed the input power, but efficiencies can be high, with a small proportion of the power dissipated as waste heat.3 Circuit description3.1 Basic designsIn one simple inverter circuit, DC power is connected to a transformer through the centre tap of the primary winding. A switch is rapidly switched back and forth to allowcurrent to flow back to the DC source following two alternate paths through one end of the primary winding and then the other. The alternation of the direction of current in the primary winding of the transformer produces alternating current (AC) in the secondary circuit.The electromechanical version of the switching device includes two stationary contacts and a spring supported moving contact. The spring holds the movable contact against one of the stationary contacts and an electromagnet pulls the movable contact to the opposite stationary contact. The current in the electromagnet is interrupted by the action of the switch so that the switch continually switches rapidly back and forth. This type of electromechanical inverter switch, called a vibrator or buzzer, was once used in vacuum tube automobile radios. A similar mechanism has been used in door bells, buzzers and tattoo guns.As they became available with adequate power ratings, transistors and various other types of semiconductor switches have been incorporated into inverter circuit designs 3.2 Output waveformsThe switch in the simple inverter described above, when not coupled to an output transformer, produces a square voltage waveform due to its simple off and on nature as opposed to the sinusoidal waveform that is the usual waveform of an AC power supply. Using Fourier analysis, periodic waveforms are represented as the sum of an infinite series of sine waves. The sine wave that has the same frequency as the original waveform is called the fundamental component. The other sine waves, called harmonics, that are included in the series have frequencies that are integral multiples of the fundamental frequency.The quality of output waveform that is needed from an inverter depends on thecharacteristics of the connected load. Some loads need a nearly perfect sine wave voltage supply in order to work properly. Other loads may work quite well with a square wave voltage.3.3 Three phase invertersThree-phase inverters are used for variable-frequency drive applications and for high power applications such as HVDC power transmission. A basic three-phase inverter consists of three single-phase inverter switches each connected to one of the three load terminals. For the most basic control scheme, the operation of the three switches is coordinated so that one switch operates at each 60 degree point of the fundamental output waveform. This creates a line-to-line output waveform that has six steps. The six-step waveform has a zero-voltage step between the positive and negative sections of the square-wave such that the harmonics that are multiples of three are eliminated as described above. When carrier-based PWM techniques are applied to six-step waveforms, the basic overall shape, or envelope, of the waveform is retained so that the 3rd harmonic and its multiples are cancelled4 History4.1 Early invertersFrom the late nineteenth century through the middle of the twentieth century, DC-to-AC power conversion was accomplished using rotary converters or motor-generator sets (M-G sets). In the early twentieth century, vacuum tubes and gas filled tubes began to be used as switches in inverter circuits. The most widely used type of tube was the thyratron.The origins of electromechanical inverters explain the source of the term inverter. Early AC-to-DC converters used an induction or synchronous AC motor direct-connected to a generator (dynamo) so that the generator's commutator reversed its connections atexactly the right moments to produce DC. A later development is the synchronous converter, in which the motor and generator windings are combined into one armature, with slip rings at one end and a commutator at the other and only one field frame. The result with either is AC-in, DC-out. With an M-G set, the DC can be considered to be separately generated from the AC; with a synchronous converter, in a certain sense it can be considered to be "mechanically rectified AC". Given the right auxiliary and control equipment, an M-G set or rotary converter can be "run backwards", converting DC to AC. Hence an inverter is an inverted converter.4.2 Controlled rectifier invertersSince early transistors were not available with sufficient voltage and current ratings for most inverter applications, it was the 1957 introduction of the thyristor or silicon-controlled rectifier (SCR) that initiated the transition to solid state inverter circuits.The commutation requirements of SCRs are a key consideration in SCR circuit designs. SCRs do not turn off or commutate automatically when the gate control signal is shut off. They only turn off when the forward current is reduced to below the minimum holding current, which varies with each kind of SCR, through some external process. For SCRs connected to an AC power source, commutation occurs naturally every time the polarity of the source voltage reverses. SCRs connected to a DC power source usually require a means of forced commutation that forces the current to zero when commutation is required. The least complicated SCR circuits employ natural commutation rather than forced commutation. With the addition of forced commutation circuits, SCRs have been used in the types of inverter circuits describedIn applications where inverters transfer power from a DC power source to an AC above.power source, it is possible to use AC-to-DC controlled rectifier circuits operating in the inversion mode. In the inversion mode, a controlled rectifier circuit operates as a line commutated inverter. This type of operation can be used in HVDC power transmission systems and in regenerative braking operation of motor control systems.Another type of SCR inverter circuit is the current source input (CSI) inverter. A CSI inverter is the dual of a six-step voltage source inverter. With a current source inverter, the DC power supply is configured as a current source rather than a voltage source. The inverter SCRs are switched in a six-step sequence to direct the current to a three-phase AC load as a stepped current waveform. CSI inverter commutation methods include load commutation and parallel capacitor commutation. With both methods, the input current regulation assists the commutation. With load commutation, the load is a synchronous motor operated at a leading power factor. As they have become available in higher voltage and current ratings, semiconductors such as transistors or IGBTs that can be turned off by means of control signals have become the preferred switching components for use in inverter circuits.4.3 Rectifier and inverter pulse numbersRectifier circuits are often classified by the number of current pulses that flow to the DC side of the rectifier per cycle of AC input voltage. A single-phase half-wave rectifier is a one-pulse circuit and a single-phase full-wave rectifier is a two-pulse circuit. A three-phase half-wave rectifier is a three-pulse circuit and a three-phase full-wave rectifier is a six-pulse circuit。

<Electrical and electronic technology>Chapter One: DC Circuit and analysis methodsThe basic concept : the composition and role of the circuit ; understand and master circuit current, voltage and electromotive force , the physical meaning of electric power and energy ; understand the meaning of the voltage and electromotive force , current reference direction ; understand and master the basic circuit element resistors, inductors, capacitors V - Ante , as well as a voltage source ( including the constant voltage source ) , the current source ( including the constant current source ) of the external characteristics ; understand circuit ( power ) of the three working status and characteristics ; understand the concept of electrical equipment ( components ) ratings , and three modes of operation ; understand the concept of the potential , understanding the relationship between the potential and voltage .Basic laws and theorems : mastering Kirchhoff's current and voltage law and Ohm's law and its applicati ons , with particular emphasis on Σ I = 0 and Σ U = significance 0:00 two sets of positive and negative numbers , and Ohm's law in the sign significance. Analysis basis and method : Understanding resistance in series or parallel , hybrid solution method to master the equivalent resistance of the resistor circuit , as well as diversion, skilled application of pressure points formula ; master the method for determining the load circuit, circuit elements , power supply , control circuit power balance analysis ; master with branch current method , the principle of superposition , Thevenin theorem and power equivalent transformation methods such as analysis, calculation circuit ; grasp calculation circuit potential of each point .Chapter 2: sinusoidal AC circuitBasic concepts : understanding the three elements of a sinusoidal AC : amplitude, frequency and initial phase ; understand the concept of RMS and the phase difference ; grasp sine amount phasor notation , master volume and conversion methods sinusoidal phase between the amount ; understanding sinusoidal instantaneous power AC circuits , reactive power, apparent power concept , master active power, power factor concept ; understand the concept of impedance ; grasp complex calculation methods , master phasor diagram of the painting .Basic laws and theorems : Understand the basic laws of phasor form circuits , as well as phasor form ohm theorem.Analysis basis and method : mastering a single parameter AC circuit voltage and current phasor relationship, that the relationship between size and phase relationships ; understand impedance in series or parallel , hybrid solution method to master the equivalent impedance of the circuit , as well as diversion, the partial pressure of the formula phasor type of skilled application ; master circuit judge ( load ) nature ; master method phasor method , phasor diagram , as well as calculating the phase relationship between the size of the relationship and the simple sinusoidal circuit ; grasp active power, reactive powerand apparent power calculation methods , to improve understanding of the inductive load power factor approach.Chapter 3 : Three-phase AC circuitBasic concepts: symmetric three-phase voltage to understand the concept of understanding the concept of the phase voltage , phase current and line voltage and line current , to understand the concept of three-phase symmetrical and asymmetrical loads understand the concept of a three-phase symmetry of the circuit, the negative voltage and current , grasp the three-phase load connection method , understand three-phase four-wire power supply circuit in the middle of the action , understanding the three-phase circuit active power , apparent power and reactive power concept of .Analysis basis and method : mastering phase symmetrical load Y connection and △connection , the line voltage and phase voltage and line current and phase current magnitude and phase relationships, and lines, calculate the phase voltages and currents ; master the three-phase unbalanced load when the Y connection and there is midline , calculate the line current and neutral current ; grasp three-phase circuit active power, apparent power and reactive power calculations.Chapter 4: Common semiconductor devicesBasic concepts : understanding the formation and unidirectional conductive semiconductor basic knowledge and PN junction ; grasp diode voltage characteristics and unidirectional conductivity characteristics, to understand the main parameters and significance diodes , master diode circuit symbol ; understanding silicon regulator the structure and main parameters of the regulator control circuit symbols ; understand the basic structure of the transistor and the current amplification, and the understanding of the characteristic curve of the transistor in the enlarged area , and the cutoff characteristics of the saturation region , the main parameters of the transistor understood master NPN type and PNP transistor circuit symbol .Analysis basis and method : the diode forward voltage withstand (positive bias ) diode conduction withstand reverse voltage ( reverse bias ) diode cutoff . When subjected to reverse breakdown voltage regulator tube current limiting resistor under the action of the voltage across the regulator stable and unchanging ( applying a reverse voltage is greater than the stable voltage , whether the person , the regulator reverse cutoff ) ; If the regulator withstand the forward voltage regulator turns on ( with the diode same ) . Ideal diode and the ideal regulator : for idealized treatment that forward voltage is zero , the reverse cutoff infinite resistance .Triode work in the enlarged area : emitter junction is forward biased voltage withstand ; collector junction withstand reverse bias voltage ;Transistors in saturation : the emitter junction is forward biased withstand voltage ; collector junction bear positive bias voltage ;Transistor in cutoff region : emitter junction withstand reverse bias voltage ; collector junction under reverse bias voltage ;Difficulties: including diodes and regulator circuit analysis , transistor three working state judgment and the judgment of the transistor type , polarity and materials. Chapter 5: Basic amplifier circuitBasic concepts : understanding the role of the composition of various common-emitter amplifier circuit part of the pole , understanding zoom works, understanding the static and dynamic amplification circuit , understand the role of quiescent operating point ; understanding amplifying circuit AC parameters: input resistance , output resistance and the magnification of the significance.Analysis basis and method : direct access and communication pathways master painting ; grasp static analysis methods: estimation method and graphical method ; grasp the DC load line painting ; grasp the dynamic analysis methods: micro- computing small signal ac equivalent circuit parameters becomes law , graphic method for qualitative analysis will ; stable quiescent operating point to understand the processes and principles ; understanding emitter 's basic characteristics and uses.Key elements: a fixed bias circuit , voltage divider type amplifier circuit quiescent operating point of the three circuits emitter and slightly changed equivalent circuit. Will draw DC path and exchange accessChapter VI : Integrated Operational AmplifierBasic concepts : operational amplifier integrated graphics symbols and pins purposes ; negative feedback amplifier circuit and depth of negative feedback ; integrated operational amplifier ideal conditions and basic performance ; analysis of three basic op amp circuit ; integrated operational amplifier basic application Circuit ( ie : addition, subtraction , integral and differential circuits ) ; consisting operational amplifier , the main parameters ; proportional arithmetic circuit , integrated operational amplifier applications ; model ideal conditions for integrated operational amplifier.Chapter 7: DC Power SupplyBasic concepts : Understanding DC power supply and the role of four areas : transformer , rectifier , filter and regulator ; understanding of single-phase half- wave bridge rectifier principle ; understand the principle of the filter circuit , voltage regulator circuit. Understand the integrated voltage regulator applications.Analysis basis and method : Mastering half-wave , bridge rectifier circuit calculating the average load voltage , current, and the calculation of the average current rectifier diode and the maximum reverse voltage. Will draw half-wave , wave bridge rectifier , and the rectifier output load current, voltage polarity.Chapter 8: combinational logic circuitBasic concepts : logical relations , and logic , or logic, non-logical , there is acorresponding basic gates , and doors, or doors and NAND gate . Combination gate circuit , a NAND gate , NOR gate , NOR gate , three-state gate , with the XOR gates and OR gates and the like. Should have a gate symbols, logic and logical expressions. Logical formula logic algebra is important to simplify the formula logical relationship should memorize and master simple formulaic approach .Analysis basis and method : combinational logic analysis and design is the focus of this chapter , in particular, is a combination of logical analysis , master steps.Difficulty: logical expression simplification and combinational logic circuit design Chapter IX : sequential logic circuitsBasic concepts : basic RS flip-flop , synchronous RS flip-flop logic symbols and logic functions , JK flip-flop and D flip-flop , is to learn the focus of this chapter. After the bistable , CP pulse leading edge trigger and the trigger edge , the difference between the symbols . Registers and counters should have analytical methods and points.Analytical basis and Methods: trigger -based , to find CP relationship between each trigger to determine the frontier or back porch , painting the output waveform , identify the key points of transition until the next pulse occurs .Difficulty: analysis of synchronous counter。

By Dr. Ray Ridley, Ridley EngineeringThe Sepic ConverterThe most basic converter that we looked at last month is the buck con-verter. It is so named because it always steps down, or bucks, the input voltage. The output of the converter is given by:Interchange the input and the output of the buck converter, and you get the second basic converter – the boost. The boost always steps up, hence its name. The output voltage is always higher than the input voltage, and is given by:What if you have an application where you need to both step up and step down, depending on the input and output voltage? You could use two cas-caded converters – a buck and a boost. Unfortunately, this requires two separate controllers and switches. It is, however, a good solution in many cases. The buck-boost converter has the de-sired step up and step down functions:The output is inverted. A flyback convert -er (isolated buck-boost) requires a trans-former instead of just an inductor , adding to the complexity of the development. One converter that provides the need-ed input-to-output gain is the Sepic (sin-gle-ended primary inductor converter) converter. A Sepic converter is shown in Fig. 1. It has become popular in recent years in battery-powered systems that must step up or down depending upon the charge level of the battery.Fig. 2 shows the circuit when the power switch is turned on. The first inductor, L1, is charged from the input voltage source during this time. The second inductor takes energy from the first capacitor, and the output capacitor is left to provide the load current. The fact that both L1 and L2 are disconnect-ed from the load when the switch is on leads to complex control characteristics, as we will see later.When the power switch is turned off, the first inductor charges the capaci -tor C1 and also provides current to the load, as shown in Fig. 3. The second inductor is also connected to the load during this time.The output capacitor sees a pulse of current during the off time, making it inherently noisier than a buck converter.The input current is non-pulsating, a dis-tinct advantage in running from a battery supply.ConverterIn the last issue, we talked about the simplest of all converters, the buck converter, and showed how its control transfer functions could be extraordinarily complex. In this issue, we’ll go to the other end of the spectrum, and look at a converter that is far more complex, yet is often used by engineers who areunaware of the difficulties that follow.Figure 1. The Sepic converter can both step up and step down the input volt-age, while maintaining the same polar-Figure 2. When the switch is turned on, the input inductor is charged from the source, and the second inductor is charged from the first capacitor. No energy is supplied to the load capaci-tor during this time. Inductor current and capacitor voltage polarities are marked in this figure.Figure 3. With the switch off, both inductors provide current to the load capacitor.The PWM Switch Model in the Sepic ConverterThe best way to analyze both the AC and DC characteristics of the Sepic converter is by using the PWM switch model, developed by Dr. Vatché Vor-périan in 1986. Some minor circuit ma-nipulations are first needed to reveal the location of the switch model, and this is Proper small-signal analysis of the Sepic converter is a difficult analytical task, only made practical by advanced circuit analysis techniques originally de-veloped by Dr. David Middlebrook and continued by Vorpérian. [1]If you’re going to build a Sepic, as a minimum, you need to understand the control characteristics. Fortunately, Vorpérian’s work is now available for this converter, and you can download the complete analysis notes .[2]The simplified analysis of the Sepic converter, derived in detail in [2], ignores parasitic resistances of the inductors and capacitors, and yields the following result for the control-to-output transferfunction:Whereshown in Fig. 4.First, capacitor C1 is moved to the bottom branch of the converter. Then, inductor L2 is pulled over to the left, keeping its ends connected to the same nodes of the circuit. This reveals the PWM switch model of the converter, with its active, passive, and common ports, allowing us to use well-estab-lished analysis results for this converter. For more background on the PWM switch model, the text book “FastAnalytical Techniques for Electrical and Electronic Circuits” [1] is highly recom-mended.DC Analysis of the Sepic Converter Fig. 5 shows the equivalent circuit of the Sepic converter with the DC portion of the PWM switch model in place. The DC model is just a 1:D transformer. We replace the inductors with short circuits, and the capacitors with open circuits for the DC analysis. You can, if you like, include any parasitic resistances in the model [2], but that’s beyond the scope of this article.After the circuit is manipulated as shown in the figure, we can write the KVL equation around the outer loop ofthe converter:Rearranging gives:And the DC gain is given by:Here we see the ability of the con-verter to step up or down, with a gain of 1 when D=0.5. Unlike the buck-boostand Cuk converters, the output is not inverted.AC Analysis of the Sepic Converter Y ou won’t find a complete analysis of the Sepic converter anywhere in printed literature. What you will find are applica -tion notes with comments like, “the Sepic is not well-understood.” Despite the lack of documentation for the converter, engi-neers continue to use it when applicable.Figure 5. For DC analysis, the smallsignal sources are set to zero, induc-tors become short circuits, and capaci-tors become open circuits. After thecircuit is redrawn, it is a trivial matter towrite KVL around the outer loop of the circuit to solve for the conversion gainof the converter.Figure 6. The small-signal AC sources are included in the switch model, and we can either solve the analysis by hand, or use PSpice to plot desired transfer functions. The hand analysis is crucial for symbolic expressions and design equations.Figure 4. In order to take advantage of Vorpérian’s PWM switch model, the circuit elements must first be rear -ranged. The function of the original topology is retained when the capaci-tor is moved, and the second inductoris redrawn.er? There are several possibilities. First, the dynamic and step load requirements on the system may be very benign, with no reason to design a loop with high bandwidth. This allows the loop gain to be reduced below 0 dB before the extreme phase delay of the second resonance.Secondly, in many practical cases, the parasitic resistances of the circuit move the RHP zeros to the left half plane, greatly reducing the phase delay. This can also be done with the addition of damping networks to the power stage, a topic beyond the scope of this article.Thirdly, some engineers do not builda proper Sepic. In some applicationnotes, the two inductors are wound on a single toroidal core, which provides almost unity coupling between the two. In this case, the circuit no longer works as a proper Sepic. Don’t fall into this design trap - the circuit will be far fromoptimum.Additional Reading [1] “Fast Analytical Techniques for Electrical and Electronic Circuits”,Vatché Vorpérian, Cambridge University Press 2002. ISBN 0 521 62442 8.[2] . Click on Articles and SepicAnalysis Notes.As you can see from these expres-sions, the “simplified” analysis is any -thing but simple. Including the para-sitic resistances greatly complicates the analysis, but may be necessary for worst-case analysis of the Sepic converter. The analysis of this converter involves the use of the powerful extra element theorem, and Vorpérian’s book on circuit analysis techniques. [1] In addition to the inevitable fourth-order denominator of the Sepic, the most important features to note in the control transfer function are the terms in the numerator. The first term is a single right-half-plane (RHP) zero. Right-half-plane zeros are a result of converters where the response to an increased duty cycle is to initially decrease the output voltage.When the power switch is turned on, the first inductor is disconnected from the load, and this directly gives rise to the first-order RHP zero. Notice that the expres-sion only depends on the input inductor, L1, the load resistor, R, and the duty cycle. The complex RHP zeros arise from the fact that turning on the switch disconnects the second inductor from the load. These zeros will actually move with the values of parasitic resistors in the circuit, so careful analysis of your converter is needed to ensure stabilityunder all conditions. PSpice Modeling of the Sepic ConverterThe analytical solution above does not include all of the parasitic circuit ele-ments. As you will see from [2], there is a prodigious amount of work to be done even without the resistances.We can also use PSpice to help un-derstand the Sepic better. Fig. 7 shows the circuit model for a specific numeri -cal application of the Sepic, and it in-cludes resistances which will affect the stability of the converter, sometimes in dramatic ways.The PSpice file listing can be down -loaded from [2] so you can reproduce these results to analyze your own Sepic converter.Fig. 8 shows the result of the PSpice analysis. The two resonant frequen-cies predicted by the hand analysis can clearly be seen in the transfer functionplot. What is remarkable is the extreme amount of phase shift after the second resonance. This is caused by the delay of the second pair of poles, and theadditional delay of the complex RHPzeros. The total phase delay throughthe converter is an astonishing 630degrees. Controlling this converter at a frequency beyond the second reso-nance is impossible.SummaryThe Sepic converter definitely hassome select applications where it is the topology of choice. How do designersget away with building such a convert-Figure 7. Analysis can also be done with PSpice. This figure shows a specific design example for a 15 W converter. Parasitic resistances are included in thePSpice model.Figure 8. This shows the control-to-output transfer function for the Sepic converter. With low values of damping resistors, the converter has four poles, and three right-half-plane zeros. This results in an extreme phase delay of630 degrees!。

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Who Is James Bond?The latest Bond film is an enormous box-office(票房)hit.But who is James Bond?Where does he come from?Author Ian Fleming,the creator of James Bond,told us something about the origins of the world's most famous secret agent.In the first Bond novel,Ian Fleming told us that James Bond was the son of a Scottish father and an Asian mother.But perhaps this was not really true.The title of the19th Bond film,“The World Is Not Enough,"was based on the Latin motto of the Bond family,which is mentioned in one of the early novels.However,it now appears that the motto is not that of the Scottish Bonds,but that of a different Bond family,who came from England.So perhaps Bond is English,not Scottish.Bond went to Eton College,the same school as his creator Ian Fleming.This is a school where young people learn how to move in high society,like Bond does so well.After leaving school,Bond did not go to university.He joined the British Secret Service.He soon got promoted to the top.From then on he was007,"Iicensed to kill",and so began a career which would take him to all the corners of the earth.In the early days,Bond's role was quite clear.He was working for the West.His main enemies were men from the KGB and other dangerous organizations.Since the end of the Cold War,the role of the Service has changed,and Bond's job profile has changed with it.Now his main enemies are the big bosses of organized crime and international terrorism.Unlike the Cold War,organized crime is unlikely to come to an end.We can therefore be sure that James Bond,the best-known English fictional hero of the20th century,has many more adventures ahead of him.1.The new Bond film made much money for its producer.A.TrueB.FalseC.Not Given【答案】A【解析】题目中的意思是这部新的邦德电影为它的制片人赚了很多钱。

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Origins of the Megaliths 1Since the days of the earliest antiquarians,scholars have been puzzled by the many Neolithic(~4000 B.C.~2200 B.C.)communal tombs known as megaliths along Europe's Atlantic seaboard.Although considerable variations are found in the architectural form of these impressive monuments,there is a general overriding similarity in design and,particularly,in the use of massive stones. 2The construction of such large and architecturally complex tombs by European barbarians struck early prehistorians as unlikely.The Bronze Age seafaring civilizations that lived in the region of the Aegean Sea(~3000 B.C.~1000 B.C.),among whom collective burial and a diversity of stone-built tombs were known,seemed a probable source of inspiration.It was suggested that Aegean people had visited Iberia in southwestern Europe in search of metal ores and had introduced the idea of collective burial in massive tombs,which then spread northward to Brittany,Britain,North Germany,and Scandinavia. 3Radiocarbon dates for a fortified settlement of megalith builders at Los Millares in Spain appeared to confirm this picture,though dates for megaliths in Brittany seemed too early.When calibrated,however,it became clear that radiocarbon dates were universally too early to support a Bronze Age Aegean origin.It is now clear that the megaliths are a western and northern European invention,not an introduced idea.Even so,they are still a subject of speculation and inquiry.What induced their builders to invest massive efforts in erecting such monumental tombs How was the necessary labor force assembled What underlies their striking similarities 4One answer to the last question was proposed by Professor Grahame Clark,one of Britain's greatest prehistorians.Investigating the megaliths of southern Sweden,he noted that one group was concentrated in coastal locations from which deep-sea fish such as cod,haddock,and ling could have been caught in winter.Historically,much of the Atlantic was linked by the travels of people who fished,and this could well have provided a mechanism by which the megalith idea and fashions in the style of tomb architecture spread between coastal Iberia,Brittany,Ireland,western England and Scotland,and Scandinavia.The high concentrations of megaliths on coasts and the surprising number of megaliths found on small islands may support a connection with fishing. 5Professor Colin Renfrew of the University of Cambridge,England,however,views the similarities as similar responses to similar needs.At the structural level,the passage that forms a major element of many graves could have been devised independently in different areas to meet the need for repeated access to the interiorof these communal tombs.Other structural resemblances could be due to similarities in the raw materials available.In answer to the question of why the idea of building monumental tombs should arise independently in a number of areas,he cites the similarities in their backgrounds. 6Most megaliths occur in areas inhabited in the postglacial period by Mesolithic hunter-gatherers(~20000 B.C.~18000 B.C.).Their adoption of agriculture through contact with Neolithic farmers,Renfrew argues,led to a population explosion in the region and consequent competition for farmland between neighboring groups.In the face of potential conflict,the groups may have found it desirable to define their territories and emphasize their boundaries.The construction of megaliths could have arisen in response to this need. 7Renfrew has studied two circumscribed areas,the Scottish islands of Arran and Rousay,to examine this hypothesis more closely.He found that a division of the arable land into territories,each containing one megalith,results in units that correspond in size to the individual farming communities of recent times in the same area.(A)Each unit supported between 10 and 50 people.(B)The labor needed to put up a megalith would probably be beyond the capabilities of a community this size.(C)But Renfrew argues that the cooperation of other communities could be secured by some form of recognized social incentive perhaps a period of feasting at which communal building was one of several activities.(D) 8Most megaliths contain collective burials.Different tombs used different arrangements,but there seems to have been an underlying theme:people placed in these tombs were representative of their society,but their identity as individuals was not important.The tombs belonged to the ancestors,through whom the living society laid claim to their land.This interpretation reinforces Renfrew’s view of the megaliths as territorial markers. 1.The word“collective”in the passage is closest in meaning to A.above ground B.public C.elaborate D.group (第2段)2.According to paragraph 2,early prehistorians thought the Aegean people of the Bronze Age might have influenced megalith building along the Atlantic seaboard because they。

The University of Cambridge is one of the oldest universities in the world, and one of the largest in the United Kingdom. It has a world-wide reputation for outstanding academic achievement and the high quality of research undertaken in a wide range of science and arts subjects. The University pioneers work in the understanding of disease, the creation of new materials, advances in telecommunications and research into the origins of the universe. It trains doctors, vets, architects, engineers and teachers. At all levels about half of the students at Cambridge study arts and humanities subjects, many of whom have gone on to become prominent figures in the arts, print and broadcast media. The University's achievements in the sciences can be measured by the sixty or more Nobel Prizes awarded to its members over the years. The University is a self-governing body: the legislative authority is the Regent House, which consists of the three thousand or so members of the teaching and administrative staff of the University and Colleges who have the MA (or MA status) or a higher degree. The principal administrative body of the University is the Council, which consists mainly of members of the academic staff elected by the Regent House. The General Board of the Faculties co-ordinates the educational policy of the University and the Finance Committee of the Council supervises its financial affairs. As Cambridge approaches its eight hundredth anniversary in 2009, it is looking to the future. The modern University is an international centre of teaching and research in a vast range of subjects: about half of the students study science or technology. Members of the University have won over sixty Nobel Prizes. It continues to change in response to the challenges it faces. The Vice-Chancellor, for instance, is no longer a Head of College, but is a full-time administrative appointment. A Development Office and associated charitable foundation is successfully seeking funds around the world for new ventures. The 1990s have seen a major expansion of University accommodation for teaching and research. There are many major new buildings either underway or already completed, including the Law Faculty building and the Judge Institute of Management Studies, in March 1996 opened by HM The Queen.。