当前位置：文档之家 › 国半公司运放应用笔记大集合AN-278

国半公司运放应用笔记大集合AN-278

  • 格式：pdf
  • 大小：259.87 KB
  • 文档页数：10

Designing with a New Super Fast Dual Norton AmplifierWHY ANOTHER NORTON AMPLIFIER?The current differencing Norton amplifier has been widely applied over the last5years because of the versatility and availability of quad Norton amplifiers(the LM3900).These low cost quads are found today in a wide variety of analog systems,but primarily in medium frequency and single sup-ply AC applications.Today,a brand new dual current differ-encing amplifier,the LM359,offers spectacular speed im-provements which can be used in circuits operating well beyond the video frequencies.How the speed is improved:The speed improvement of the new Norton amplifier is due to the cascode circuit(Figure 1).Cascode circuits are used in high frequency single-ended amplifier designs because there is no Miller effect on the collector-to-base capacitance of the input transistor.Also, there is no collector-to-emitter parasitic feedback in the com-mon base configured transistor,Q2,so the high frequency signal appearing at the output of the cascode does not re-flect back into the input.Furthermore,note that band-limiting PNP transistors are eliminated from the signal path;here PNPs are used only for collector loads,so not only is high speed maintained,but high gain is also obtained without ad-ditional amplification stages.Adding a mirror to get differential inputs:To make the high frequency single-ended amplifier more versatile differ-ential inputs should be provided.An easy way is to add a cur-rent mirror across the negative(inverting)input terminal(Fig-ure2).This method provides current differencing,as the current entering the non-inverting input is extracted from the inverting input current.The LM359is then a current differ-encing,as opposed to a voltage differencing,op amp.The programmable features extend versatility:An addi-tional feature of the LM359is the programmability of its speed,its input impedance,and its output current sinking ca-pability for line driver applications and for control of overall power consumption(Figure3).An internal compensation ca-pacitor is adequate compensation for all inverting applica-tions where the gain is10or higher.An additional compensa-tion capacitor can be added externally to reduce undesired bandwidth or to fit any particular application,as will be dis-cussed later.The following sections illustrate some new de-sign ideas using this fast Norton amplifier.A NEW HIGH FREQUENCY ACTIVE FILTER STRUCTUREMultiple op amp active filter building blocks are very popular because of their low sensitivities and their tunability.The ba-sic element of such a filter is the inverting ually two inverting integrators are cascaded and a third inverter al-lows closing the overall loop with the proper phase.This is the idea behind the state variable and bi-quad filter struc-tures which today are fully available in low cost hybridforms.The op amp count in these filters could be reduced by one(allowing use of a dual op amp instead of 3op amps or a quad)if a true non-inverting integrator could be built with a single op amp.Unfortunately,this cannot be done with stan-dard op amps but is a trivial task with current differencing amplifiers (Figure 4).Combining a non-inverting integrator with an inverting one,a new high frequency and low sensitiv-ity active filter building block can be made (Figure 5).Table 1shows the 3particular filter structures,together with their de-sign equations,which are derived from Figure 5.The fre-quency compensation for the 2amplifiers is asymmetric to optimize performance.Also,since the LM359is a wide band-width amplifier,high frequency circuit layout is strongly rec-ommended.The circuit works with a single supply,and the output DC biasing of each filter type is provided with 2resis-tors,R1and R b ,which should be chosen according to Table 2.TABLE 1.Analysis and Design EquationsType V O1V O2C i R i2R i1f oQ of Z (Notch)H o (LP)H o (BP)H o (HP)IBPLPOR i2∞––II HP BP C i ∞∞––IIINotch or Band-Reject–C i ∞R i1––TABLE 2.DC Biasing Equations forV O1(DC)≅V O2(DC)≅V +/2Type IType IIType III 2Theoperating range of an active filter can beestimated by comparing itsQ o,center frequency product (f o x Q o ),with the gain bandwidth product (GBW)of its active elements.The f o x Q o should be less than the active element GBW by a factor of at least 20;a higher factor will yield less sensitive filters.For instance,with a 5MHz op amp,the f o x Q o product of the filter should not exceed 250kHz,and in reality should be even less.The filters tested with the LM359could extend their f o x Q o product up to 2MHz.VOLTAGE-CONTROLLED LOW PASS FILTERA most unique feature of the LM359is that it provides the user with complete control of its frequency response over a very wide range.The combination of both programmable in-put stage current and external compensation capability is the key to this flexibility.One of the most simple,yet illustrative,examples of the use-fulness of this capability is the voltage-controlled low pass fil-ter shown in Figure 6.The corner frequency of this filter is determined by the closed loop corner frequency of the invert-ing,gain of 100amplifier.This frequency is directly con-trolled by the frequency of the dominant pole of the amplifi-er’s open loop response,which can be approximated by the expression:where A VOL is the amplifier’s DC open loop gain,V T is equal to KT/q or 0.026V at room temperature,I SET IN is the input stage programming current,and C COMP is the total compen-sation capacitance.The closed loop corner frequency,which,as stated is also the corner frequency of the filter,is:f c =β•GBW =β•A VOL •f pwhere βis the feedback factor,R1/(R1+R2),and a single pole open loop frequency response is bining these two expressions,the corner frequency is:AN007490-6FIGURE 6.Voltage-Controlled Low Pass Filter.Minimum Input Frequency is Determinedby C1and Thesimplest method to dynamically control f c isto vary I SETINthrough acontrol voltage,V C ,where:In this manner,C COMP should be chosen for the highest de-sired corner frequency at maximum I SET IN .Two curves illus-trating the dependence of the corner frequency on I SET IN for two different compensation capacitors are shown in Figure 7.It should be noted that as the compensation capacitor is in-creased,or I SET IN is decreased,the maximum slew rate of the amplifier is decreased.To prevent slew rate induced dis-tortion of sinusoidal input signals,the following restriction ap-plies:where V o peak is the peak output voltage of the filter and ωis 2πf IN ,where f IN is the signal frequency.The output volt-age for signal frequencies less than the corner frequency of the filter (within the passband)should then be restricted to:VIDEO AMPLIFIERSThe basic principle behind the design of the LM359is to pro-vide amplification of high frequency signals with the ease of using standard operational amplifiers.The most obvious ap-plication area for this amplifier is in the video area where a fair amount of gain is required at frequencies much higher than monolithic op amps can provide.A specific application is the amplification or buffering of a composite video signal for a distributed monitor system.Figure 8shows a typical connection for a non-inverting video amplifier whose signal source may be either detected video from a receiver,or possibly a camera signal.The output stage of the LM359can be programmed,as shown,to drive a terminated 75Ωcable to 4Vp-p for use as a video line driver.For color signals,the differential phase error and dif-ferential gain error at 3.58MHz are desirably low,as noted in Table 3.TABLE 3.Typical Video Amplifier Performance A V =20dB −3dB Bandwidth → 2.5Hz to 25MHz Differential Phase Error <1˚at 3.58MHz Differential Gain Error <2%at 3.58MHz Amplifier Output Swing =4Vp-p MaxFor general purpose wideband amplifiers,the availability of two amplifiers in a single package allows cascading two gain stages to achieve very high gain bandwidth products as shown in Figure 9.DISC AND MAGNETIC TAPE MEMORY SENSING In digital data recovery from a magnetic storage medium,such as a disc or magnetic tape,there exists a need for high gain bandwidth amplifiers to convert the low level voltage transients from the output of the playback head (caused by a magnetic flux reversal on the tape or disc)to digital pulses that can be processed by data separating or decoding cir-cuitry.The two amplifiers in a single LM359package can be combined in a variety of ways to provide the basic blocks of a playback channel.a)For very high bit rates and low level signals they can becascaded to optimize overall gain bandwidth product,as already shown in Figure 9.b)For single-ended playback signals (non center-tappedhead),one amplifier can be used as a gain stage and the other as a differentiating stage to convert recovered sig-nal peaks into bi-directional zero crossing signals,and then properly drive a comparator with regard to direction of flux changes on the disc or tape;this simplifies decod-ing of phase-encoded data.c)For differential playback signals (center-tapped head),one amplifier can be used to provide gain for each output signal individually to retain the differential signal,or a single amplifier difference amp can perform a differential to single-ended conversion and the other amplifier can perform differentiation of the single-ended signal.For multi-channel,parallel recorded data,the overall compo-nent count of the playback system can be minimized by using one amplifier of the LM359per channel.AN007490-7FIGURE 7.Amplifier Closed Loop CornerFrequency vs I SET IN 4Combininggain with constant delay filtering:Another im-portantapplication of the LM359in data recoverysystems is that of filtering.It is most desirable to prevent high frequency noise spikes from being coupled through the sensing stage causing erroneous readings,but the low pass filter used must not induce time delays to valid data signals which will be decoded by their time relationship to each other.This im-mediately implies a constant group delay low pass filter or a Bessel filter approximation which,if implemented with active components,can also provide signal gain.Figure 10shows a fourth order,250kHz,gain of 100Bessel filter.Here,be-cause of the low Q o requirements of the Bessel filter,a simple (Sallen-Key)filter structure has been chosen over the previously discussed higher performance structures.Note,however,that constant group delay filtering and amplification are performed with a single package.A HANDLE ON INPUT NOISEThe programmability of the amplifier’s input stage current and the ability to “shut off”the non-inverting input current mirror allows significant improvements of the noise charac-teristics.For an inverting application where the non-inverting input would only be used for DC biasing purposes,an alter-nate biasing scheme,the nV BE biasing,can be used,as shown in Figure 11.This allows “shutting off”the input cur-rent mirror which,in itself,will reduce the input noise by a factor of two.In addition,the input stage programming current can be in-creased to further reduce the noise voltage at the expense of an increase in input noise current and low frequency 1/f noise,which are not a problem in low input impedance,wide-band amplifiers.The typical effect on noise vs input stage current is illustrated in Figure 12.AN007490-8FIGURE 8.A Typical Application of this Fast Norton Amplifier as a High Perfomance Video Amplifier Driving a 75ΩLineAN007490-9FIGURE 9.General Purpose,High Gain,Wideband Amplifiers Can Be Obtained byCascading the 2Norton Amplifiers Available on a Single ChipMAKINGA FAST JFET INPUT OP AMPThe currentmirror input stage of theLM359can be used as an active load for a differential JFET stage to form a super fast op amp (Figure 13).This circuit combines the high fre-quency performance and programmability of the LM359with the high input impedance and low bias currents of a discrete JFET input stage.External compensation of the LM359is generally required to accommodate any additional phaseshift of the input stage,and the “pole-splitting”configuration shown works quite well.The speed performance is shown in Table 4.Note that this op amp should be mainly used for very high speed,single supply AC coupled circuits.This is because the op amp DC input offset voltage depends mainly on the matching of 2discrete JFETs.FIGURE 10.A Fourth Order,250kHz Bessel Filter for Data Recovery Systems.The Filtering Function is Done with a Single Package.AN007490-11FIGURE 11.nV BE Biasing Can Reduce Input Noise VoltageAN007490-12a)Effect of “Shutting Off”the Input MirrorAN007490-18b)Noise Performance of Figure 11FIGURE 12.Programmability Provides a Handle on Input Noise 6TABLE 4.Typical AmplifierPerformanceA V BW Sr C C 140MHz 60V/µs 51pF 1024MHz 130V/µs 5pF 1004.5MHz150V/µs2pFA HIGH COMMON-MODE INPUT VOLTAGE DIFFERENCE AMPLIFIERAn inherent feature of a current differencing input stage is that the voltages from which the input currents are derived are limited only by the maximum input current (or mirror cur-rent)of the amplifier and the size of the input resistors.An application that takes advantage of this is a highcommon-mode voltage difference amplifier (Figure 14).In this circuit,the LM359will amplify the difference in voltage between inputs V1and V2,but both inputs can be riding on a common-mode level as high as approximately 250V D -C without exceeding the maximum mirror current of 10mA.The addition of resistor R1in Figure 14allows an adjustment of the common-mode rejection ratio by adjusting the invert-ing input bias current,via the programmable input stage cur-rent,I SET IN .This bias current error is most significant at lower common-mode input voltage levels.By making the bias current directly proportional to the input level,a 20dB CMRR improvement is possible by adjusting R1for maxi-mum CMRR at the maximum input common-mode voltage.BUILDINGA FAST AND ULTRA LINEAR V/F CONVERTERLinearand fast voltage-to-frequency (V/F)converters arevery difficult to build,especially when standard V/F design techniques are used.A solution to this problem is the use of a fast phase locked loop (PLL)which is driven by a medium frequency and ultra linear V/F IC (the LM331),Figure 15.This high frequency operation is obtained via a frequency di-vider inserted into the loop,and the linearity of the overall cir-cuit closely approximates the linearity of the medium fre-quency input V/F.The high frequency,quasi linear VCO,and the error amplifier of the PLL are designed by using the 2sections of the LM359.The output frequency of the VCO,which is also the output of the system,is divided by 100and is compared with the output of the driving V/F via a digital phase detector.The overall circuit is shown in Figure 16.Fol-lowing a zero and a full-scale adjust,the V/F works well over 2decades of frequency and its non-linearity is below 0.03%,as shown in Figure 17.AN007490-16FIGURE 17.Typical Performance 8REFERENCESFredericksen,T.M.;Howard,W.M.;Sleeth,R.S.,“The LM3900—A NewCurrent-Differencing Quad of ±InputAm-plifiers”AN-72,National Semiconductor Corporation.Nortronics Design Digest on Digital Recording,Application Factors to Consider for Magnetic Heads,1976.Pease,R.A.,“New Phase-Locked-Loops Have Advantages as Frequency to Voltage Converters (and more)”AN-210,National Semiconductor Corporation.9Book Extract EndLIFESUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FORUSE AS CRITICAL COMPONENTSIN LIFESUPPORT DE-VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-CONDUCTOR CORPORATION.As used herein:1.Life support devices or systems are devices or sys-tems which,(a)are intended for surgical implant into the body,or (b)support or sustain life,and whose fail-ure to perform when properly used in accordance with instructions for use provided in the labeling,can be reasonably expected to result in a significant injury to the user.2.A critical component in any component of a life support device or system whose failure to perform can be rea-sonably expected to cause the failure of the life support device or system,or to affect its safety or effectiveness.National Semiconductor Corporation AmericasTel:1-800-272-9959Fax:1-800-737-7018Email:support@National Semiconductor EuropeFax:+49(0)180-5308586Email:europe.support@Deutsch Tel:+49(0)180-5308585English Tel:+49(0)180-5327832Français Tel:+49(0)180-5329358Italiano Tel:+49(0)180-5341680National Semiconductor Asia Pacific Customer Response Group Tel:65-2544466Fax:65-2504466Email:sea.support@National Semiconductor Japan Ltd.Tel:81-3-5620-6175Fax:81-3-5620-6179A N -278D e s i g n i n g w i t h a N e w S u p e r F a s t D u a l N o r t o n A m p l i f i e rNational does not assume any responsibility for use of any circuitry described,no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.。

合集下载

公司理财原版题库Chap010

公司理财原版题库Chap010

Chapter 10Return and Risk: The Capital-Assets-Pricing Model Multiple Choice Questions1. When a security is added to a portfolio the appropriate return and risk contributions areA) the expected return of the asset and its standard deviation.B) the expected return and the variance.C) the expected return and the beta.D) the historical return and the beta.E) these both can not be measured.Answer: C Difficulty: Medium Page: 2552. When stocks with the same expected return are combined into a portfolioA) the expected return of the portfolio is less than the weighted average expected return of thestocks.B) the expected return of the portfolio is greater than the weighted average expected return of thestocks.C) the expected return of the portfolio is equal to the weighted average expected return of thestocks.D) there is no relationship between the expected return of the portfolio and the expected return ofthe stocks.E) None of the above.Answer: C Difficulty: Easy Page: 2613. Covariance measures the interrelationship between two securities in terms ofA) both expected return and direction of return movement.B) both size and direction of return movement.C) the standard deviation of returns.D) both expected return and size of return movements.E) the correlations of returns.Answer: B Difficulty: Medium Page: 258-259Use the following to answer questions 4-5:GenLabs has been a hot stock the last few years, but is risky. The expected returns for GenLabs are highly dependent on the state of the economy as follows:State of Economy Probability GenLabs ReturnsDepression .05 -50%Recession .10 -15Mild Slowdown .20 5Normal .30 15%Broad Expansion .20 25Strong Expansion .15 404. The expected return on GenLabs is:A) 3.3%B) 8.5%C) 12.5%D) 20.5%E) None of the above.Answer: C Difficulty: Medium Page: 256Rationale:E(r) = .05(-.5) + .10(-.15) + .2(.05) + .3(.15) + .2(.25) + .15(.40) = .125 = 12.5%5. The variance of GenLabs returns isA) .0207B) .0428C) .0643D) .0733E) None of the above.Answer: B Difficulty: Medium Page: 256-257Rationale:.05(-.50 - .125)2 + .1(-.15 - .125)2 + .2(.05 - .125)2 + .3(.15 - .125)2 + .2(.25 - .125)2 + .15(.40 - .125)2 = .04286. The standard deviation of GenLabs returns isA) .0845B) .2069C) .3065D) .3358E) None of the above.Answer: B Difficulty: Medium Page: 256-257Rationale:.05(-.50 - .125)2 + .1(-.15 - .125)2 + .2(.05 - .125)2 + .3(.15 - .125)2 + .2(.25 - .125)2 + .15(.40 - .125)2 = .0428(.0428) = .20697. The correlation between two stocksA) can take in positive values.B) can take on negative values.C) cannot be greater than 1.D) cannot be less than -1.E) All of the above.Answer: E Difficulty: Medium Page: 260-2618. If the correlation between two stocks is –1, the returnsA) generally move in the same direction.B) move perfectly opposite one another.C) are unrelated to one another as it is < 0.D) have standard deviations of equal size but opposite signs.E) None of the above.Answer: B Difficulty: Medium Page: 2609. Stock A has an expected return of 20%, and stock B has an expected return of 4%. However, therisk of stock A as measured by its variance is 3 times that of stock B. If the two stocks arecombined equally in a portfolio, what would be the portfolio's expected return?A) 4%B) 12%C) 20%D) Greater than 20%E) Need more information to answer.Answer: B Difficulty: Medium Page: 262Rationale:Rp = 20(.5) + 4(.5) = 12%Use the following to answer questions 10-14:Idaho Slopes (IS) and Dakota Steppes (DS) are both seasonal businesses. IS is a downhill skiing facility, while DS is a tour company that specializes in walking tours and camping. The equally likely returns on each company over the next year is expected to be:Economy Idaho Slopes Dakota SteppesStrong Downturn -10% 2%Mild Downturn - 4% 7%Slow Growth 4% 6%Moderate Growth 12% 4%Strong Growth 20% 4%10. The mean expected returns of Idaho Slopes and Dakota Steppes areA) 4.0%; 6.0%B) 4.4%; 4.6%C) 5.5%; 5.8%D) 10.0%; 6.0%E) None of the aboveAnswer: B Difficulty: Medium Page: 256Rationale:IS = (-10%-4%+4%+12%+20%)/5 = 4.4%DS = (2%+7%+6%+4%+4%)/5 = 4.6%11. The variances of Idaho Slopes and Dakota Steppes areA) .0145; .00038B) .011584; .000304C) .006454; .000154D) .0008068; .000193E) None of the aboveAnswer: B Difficulty: Hard Page: 256-257Rationale:2IS = .2 = 0.0115842DS = .2 = .00030412. The covariance between the Idaho Slopes and Dakota Steppes returns isA) .00187B) .00240C) .00028D) .000056E) None of the aboveAnswer: C Difficulty: Hard Page: 258-259Rationale:ISDS = = .0002813. If Idaho Slopes and Dakota Steppes are combined in a portfolio with 50% invested in each, theexpected return and risk would be?A) 4.5%; 0%B) 4.5%; 5.48%C) 5.0%; 0%D) 5.625%; 37.2%E) 8.0%; 8.2%Answer: B Difficulty: Hard Page: 261-262Rationale:Rp = .5(.044) + .5(.046) = .045 = 4.5%p = .5 = .05477 = 5.48%14. The correlation between stocks A and B is theA) covariance between A and B divided by the standard deviation of A times the standarddeviation of B.B) standard deviation A divided by the standard deviation of B.C) standard deviation of B divided by the covariance between A and B.D) variance of A plus the variance of B dividend by the covariance.E) None of the above.Answer: A Difficulty: Medium Page: 26015. A portfolio is entirely invested into Buzz's Bauxite Boring Equity, which is expected to return 16%,and Zum's Inc. bonds, which are expected to return 8%. Sixty percent of the funds are invested in Buzz's and the rest in Zum's. What is the expected return on the portfolio?A) 6.4%B) 9.6%C) 12.8%D) 24.2%E) Need additional information.Answer: C Difficulty: Medium Page: 262Rationale:R p = .60(R Buzz)+.40(R Zum) = .60(16%) + .40(8%) = 12.8%16. You have plotted the data for two securities over time on the same graph, ie., the month return ofeach security for the last 5 years. If the pattern of the movements of the two securities rose and fell as the other did, these two securities would haveA) no correlation at all.B) a weak negative correlation.C) a strong negative correlation.D) a strong positive correlation.E) one can not get any idea of the correlation from a graph.Answer: D Difficulty: Easy Page: 26017. If the covariance of stock 1 with stock 2 is -.0065, then what is the covariance of stock 2 with stock1?A) -.0065B) +.0065C) greater than +.0065D) less than -.0065E) Need additional information.Answer: A Difficulty: Medium Page: 258-25918. If you have a portfolio of two risky stocks which turns out to have no diversification benefit. Thereason you have no diversification is the returnsA) are too small.B) move perfectly opposite of one another.C) are too large to offset.D) move perfectly with one another.E) are completely unrelated to one another.Answer: D Difficulty: Easy Page: 26419. A portfolio will usually containA) one riskless asset.B) one risky asset.C) two or more assets.D) no assets.E) None of the above.Answer: C Difficulty: Easy Page: 26120. The variance of Stock A is .004, the variance of the market is .007 and the covariance between thetwo is .0026. What is the correlation coefficient?A) .9285B) .8542C) .5010D) .4913E) .3510Answer: D Difficulty: Medium Page: 260Rationale:Standard deviation of B = .06325, Standard deviation of the market = .08366CORR = COV/(SDA)(SDM) = .0026/(.06325)(.08366) = .491321. If the correlation between two stocks is +1, then a portfolio combining these two stocks will have avariance that isA) less than the weighted average of the two individual variances.B) greater than the weighted average of the two individual variances.C) equal to the weighted average of the two individual variances.D) less than or equal to average variance of the two weighted variances, depending on otherinformation.E) None of the above.Answer: C Difficulty: Medium Page: 26422. The opportunity set of portfolios isA) all possible return combinations of those securities.B) all possible risk combinations of those securities.C) all possible risk-return combinations of those securities.D) the best or highest risk-return combination.E) the lowest risk-return combination.Answer: C Difficulty: Medium Page: 26723. A portfolio has 50% of its funds invested in Security One and 50% of its funds invested in SecurityTwo. Security One has a standard deviation of 6. Security Two has a standard deviation of 12. The securities have a coefficient of correlation of .5. Which of the following values is closest toportfolio variance?A) .0027B) .0063C) .0095D) .0104E) One must have covariance to calculate expected value.Answer: B Difficulty: Medium Page: 262Rationale: Var. = .52(.06)2 + .52(.12)2 + 2(.5)(.5)(.5)(6)(12) = .0009 + .0036 + .0018 = .006324. A portfolio has 25% of its funds invested in Security C and 75% of its funds invested in Security D.Security C has an expected return of 8% and a standard deviation of 6. Security D has an expected return of 10% and a standard deviation of 10. The securities have a coefficient of correlation of .6.Which of the following values is closest to portfolio return and variance?A) .090; .0081B) .095; .001675C) .095; .0072D) .100; .00849E) Cannot calculate without the number of covariance terms.Answer: C Difficulty: Medium Page: 261-262Rationale:E(R) = .25(.08) + .75(.10) = .095 = 9.5%Variance = .252(.06)2 + .752(.10)2 + 2(.25)(.75)(.06)(.60)(.10) = .007225. When many assets are included in a portfolio or index the risk of the portfolio or index will beA) greater than the risk of the securities because the correlations are greater than 1.B) equal to the risk of the securities because the correlations are equal to 1.C) less than the risk of the securities because the correlations are usually less than 1.D) unaffected by the risk of securities because their correlations are less than 1.E) None of the above.Answer: C Difficulty: Medium Page: 26426. The efficient set of portfoliosA) contains the portfolio combinations with the highest return for a given level of risk.B) contains the portfolio combinations with the lowest risk for a given level of return.C) is the lowest overall risk portfolio.D) Both A and BE) Both A and C.Answer: D Difficulty: Medium Page: 26727. Diversification can effectively reduce risk. Once a portfolio is diversified the type of riskremaining isA) individual security risk.B) riskless security risk.C) risk related to the market portfolio.D) total standard deviations.E) None of the above.Answer: C Difficulty: Easy Page: 27428. For a highly diversified equally weighted portfolio with a large number of securities, the portfoliovariance isA) the average covariance.B) the average expected value.C) the average variance.D) the weighted average expected value.E) the weighted average variance.Answer: A Difficulty: Medium Page: 273-27429. A well-diversified portfolio has negligibleA) expected return.B) systematic risk.C) unsystematic risk.D) variance.E) Both C and D.Answer: C Difficulty: Easy Page: 27430. The CML is the pricing relationship betweenA) efficient portfolios and beta.B) the risk-free asset and standard deviation of the portfolio return.C) the optimal portfolio and the standard deviation of portfolio return.D) beta and the standard deviation of portfolio return.E) None of the above.Answer: C Difficulty: Medium Page: 27931. The SML is the equilibrium pricing relationship forA) efficient portfolios.B) single securities.C) inefficient portfolios.D) All of the above.E) None of the above.Answer: D Difficulty: Easy Page: 285-28632. A typical investor is assumed to beA) a fair gambler.B) a gambler.C) a single security holder.D) risk averse.E) risk neutral.Answer: D Difficulty: Medium Page: 27533. You've owned a share of stock for 6 years. It returned 5% in 3 of those years and -5% in the other3. What was the variance?A) 0B) .0015C) .0030D) .0150E) .0400Answer: C Difficulty: Medium Page: 256-257Rationale:VAR= {(5-0)2 + (5-0)2 +(5-0)2 + (5-0)2 +(5-0)2 + (5-0)2/5 - 3034. The total number of variance and covariance terms in portfolio is N2. How many of these would be(including non-unique) covariance's?A) NB) N2C) N2 - ND) N2 - N/2E) None of the above.Answer: C Difficulty: Medium Page: 27235. Total risk can be divided intoA) standard deviation and variance.B) standard deviation and covariance.C) portfolio risk and beta.D) systematic risk and unsystematic risk.E) portfolio risk and covariance.Answer: D Difficulty: Easy Page: 27436. Beta measuresA) the ability to diversify risk.B) how an asset covaries with the market.C) the actual return on an asset.D) the standard of the assets' returns.E) All of the above.Answer: B Difficulty: Medium Page: 28337. The dominant portfolio with the lowest possible risk measures isA) the efficient frontier.B) the minimum variance portfolio.C) the upper tail of the efficient set.D) the tangency portfolio.E) None of the above.Answer: B Difficulty: Medium Page: 26638. The measure of beta associates most closely withA) idiosyncratic risk.B) risk-free return.C) systematic risk.D) unexpected risk.E) unsystematic risk.Answer: C Difficulty: Easy Page: 26939. An efficient set of portfolios isA) the complete opportunity set.B) the portion of the opportunity set below the minimum variance portfolio.C) only the minimum variance portfolio.D) the dominant portion of the opportunity set.E) only the maximum return portfolio.Answer: D Difficulty: Medium Page: 27040. A stock with a beta of zero would be expected to have a rate of return equal toA) the risk-free rate.B) the market rate.C) the prime rate.D) the average AAA bond.E) None of the above.Answer: A Difficulty: Medium Page: 28541. The combination of the efficient set of portfolios with a riskless lending and borrowing rate resultsinA) the capital market line which shows that all investors will only invest in the riskless asset.B) the capital market line which shows that all investors will invest in a combination of theriskless asset and the tangency portfolio.C) the security market line which shows that all investors will invest in the riskless asset only.D) the security market line which shows that all investors will invest in a combination of theriskless asset and the tangency portfolio.E) None of the above.Answer: B Difficulty: Medium Page: 27842. According to the CAPMA) the expected return on a security is negatively and non-linearly related to the security's beta.B) the expected return on a security is negatively and linearly related to the security's beta.C) the expected return on a security is positively and linearly related to the security's variance.D) the expected return on a security is positively and non-linearly related to the security's beta.E) the expected return on a security is positively and linearly related to the security's beta.Answer: E Difficulty: Easy Page: 28243. The diversification effect of a portfolio of two stocksA) increases as the correlation between the stocks declines.B) increases as the correlation between the stocks rises.C) decreases as the correlation between the stocks rises.D) Both A and C.E) None of the above.Answer: A Difficulty: Medium Page: 26644. The elements along the diagonal of the Variance / Covariance matrix areA) covariances.B) security weights.C) security selections.D) variances.E) None of the above.Answer: D Difficulty: Medium Page: 27245. The elements in the off-diagonal positions of the Variance / Covariance matrix areA) covariances.B) security selections.C) variances.D) security weights.E) None of the above.Answer: A Difficulty: Medium Page: 27246. The separation principle states that an investor willA) choose any efficient portfolio and invest some amount in the riskless asset to generate theexpected return.B) choose an efficient portfolio based on individual risk tolerance or utility.C) never choose to invest in the riskless asset because the expected return on the riskless asset islower over time.D) invest only in the riskless asset and tangency portfolio choosing the weights based onindividual risk tolerance.E) All of the above.Answer: D Difficulty: Medium47. The beta of a security is calculated byA) dividing the covariance of the security with the market by the variance of the market.B) dividing the correlation of the security with the market by the variance of the market.C) dividing the variance of the market by the covariance of the security with the market.D) dividing the variance of the market by the correlation of the security with the market.E) None of the above.Answer: A Difficulty: Medium Page: 28348. If investors possess homogeneous expectations over all assets in the market portfolio, when risklesslending and borrowing is allowed, the market portfolio is defined toA) be the same portfolio of risky assets chosen by all investors.B) have the securities weighted by their market value proportions.C) be a diversified portfolio.D) All of the above.E) None of the above.Answer: D Difficulty: Medium Page: 28049. A portfolio contains two assets. The first asset comprises 40% of the portfolio and has a beta of 1.2.The other asset has a beta of 1.5. The portfolio beta isA) 1.35B) 1.38C) 1.42D) 1.50E) 1.55Answer: B Difficulty: Medium Page: 287Rationale:βp = .4(1.2)+.6(1.5)=1.3850. A portfolio contains four assets. Asset 1 has a beta of .8 and comprises 30% of the portfolio. Asset2 has a beta of 1.1 and comprises 30% of the portfolio. Asset3 has a beta of 1.5 and comprises 20%of the portfolio. Asset 4 has a beta of 1.6 and comprises the remaining 20% of the portfolio. If the riskless rate is expected to be 3% and the market risk premium is 6%, what is the beta of theportfolio?A) 0.80B) 1.10C) 1.19D) 1.25E) 1.40Answer: C Difficulty: Hard Page: 287Rationale:βp = .3(.8)+.3(1.1)+.2(1.5)+.2(1.6)=1.1951. The characteristic line is graphically depicted asA) the plot of the relationship between beta and expected return.B) the plot of the returns of the security against the beta.C) the plot of the security returns against the market index returns.D) the plot of the beta against the market index returns.E) None of the above.Answer: C Difficulty: Medium Page: 281-28252. Recent research by Fama and French calls into questions the CAPM because they findA) average security returns are negatively related to the firm P/E and M/B ratios.B) P/E and M/B are only two of several factors explaining average returns.C) a weak relationship between average returns and beta for 1941 to 1990 and no relationshipfrom 1963 to 1990.D) Both A and C.E) Both B and C.Answer: D Difficulty: Hard Page: 29553. Further study to evaluate the Fama-French results and the CAPM are needed becauseA) P/E and M/B may be two of a large set of factors which were found due to hindsight bias.B) A positive relationship is found over the period 1927 to 1990 indicating more than 50 years ofdata are necessary for proper CAPM testing.C) Annual data based estimates of beta show positive relationships to average returns, whilemonthly betas do not.D) All of the above.E) None of the above.Answer: D Difficulty: Hard Page: 295-296Essay Questions54. Given the following data:Year Returns – Ink, Inc. Returns – S & P 500 1 10% 15% 2 0% -2% 3 -5% -2% 4 15 10% 5 5% 0%Calculate the covariance between Ink and the S&P 500.Difficulty: Hard Page: 258-259 Answer:R I IRR I - IR R SP SP R R SP –SP R.10 .05 .05 .15 .042.108 .00 .05 -.05 -.02 .042 -.062 -.05 .05 -.10 -.02 .042 -.062 .15 .05 .10 .10 .042 .058 .05.05.00 .00 .0421-.042(R I - I R ) x (R SP –SP R ).05 x.108 .0054 -.05 x -.062 .0031 -.10 x -.062 .0062 .10 x .058 .00580 x -.402.0205/5=.004155. A portfolio is made up of 75% of stock 1, and 25% of stock 2. Stock 1 has a variance of .08, andstock 2 has a variance of .035. The covariance between the stocks is -.001. Calculate both the variance and the standard deviation of the portfolio. Difficulty: Medium Page: 262 Answer: σ² = (.75)²(.08) + (.25)²(.035) + 2(.25)(.75)(-.001) = .0468 σ = .216356. Illustrate and explain the impact of adding securities to a portfolio assuming the securities are ofaverage correlation with each other. Difficulty: Medium Page: 274Answer:As N increases, portfolio risk decreases. As N gets large, portfolio risk approaches the market risk.For details please refer to the text Figure 10.7 page 274.57. Given the following information on 3 stocks:Stock A Stock B Stock C T-Bills Market PortExp. Return .19 .15 .09 .07 .18Variance .0200 .1196 .0205 .0000 .0064Covariance withMkt Portfolio .007 .0045 .0013 .0000 .0064Using the CAPM, calculate the expected return for Stock's A, B, and C. Which stocks would you recommend purchasing?Difficulty: Hard Page: 285-287Answer:B A = .0070/.0064 = 1.094; ra = .07 + (.18-.07)1.094 = .1903B B = .0045/.0064 = 0.703; rb = .07 + (.18-.07)0.703 = .1473B C = .0013/.0064 = 0.203; rc = .07 + (.18-.07)0.203 = .0.923Indifferent on A as .1903 = .19.Would buy B as .15 > .1473.Would not buy C as .09 < .0923.58. Returns for the IC Company and for the S&P 500 Index over the previous 4-year period are givenbelow:Year IC Co. S & P 5001 30% 17%2 0% 20%3 -8% 7%4 0% 5%What are the average returns on IC and on the S&P 500 index? If you had invested $1.00 in IC, how much would you have had after 4 years? What is the correlation between the returns on IC and the S&P?Difficulty: Medium Page: 259Answer:Average return is 22/4 = 5.5% for IC and 49/4 = 12.25% for the S&P.After 4 years $1.00 in IC grows to $1.00(1.30)(.92) = 1.196 = $1.20.For n=4σIC = 14.52, σSP = 6.38, σIC,SP = 46.125, determining ( r IC,SP ) =0.498For n-1 = 3σIC = 16.76 σSP = 7.37 σIC,SP = 61.50 determining (r IC,SP ) =. 49859. Draw and explain the relationship between the opportunity set for a two asset portfolio when thecorrelation is: [Choose from -1, -.5, 0, +.5, and +1] Difficulty: Hard Page: 267-268 Answer: ∙ Opportunity set is made up of a portfolio of two asset combinations with weights from (0,100) to (100,0). ∙ Upper point--maximum return portfolio, 100% in highest return sec. ∙ Inflection point--minimum variance portfolio ∙ See diagram, pg. 267MRPStd. DeviationRpOpportunity SetBetween the MVP (Minimum Variance Portfolio) andthe MRP (Maximum Return Portfolio) is the efficient set of portfolios.60. The diagram below represents an opportunity set for a two asset combination. Indicate the correctefficient set with labels; explain why it is so. Difficulty: Hard Page: 267-268 Answer: ∙ Efficient set is portion of opportunity set that dominates. ∙ Provides maximum return for given risk or converse.MRPStd. DeviationRpOpportunity SetA is on the efficient frontier with the best return to risk combination. Portfolioson the frontier dominate all other portfolios. A dominates both B and C. B has a higher standard deviation for the same return while C has a lower return for the same standard deviation.ABCXX。

ANSI IEEE C57.110-1986

ANSI IEEE C57.110-1986

ANSI/IEEE C57.110-1986
An American National Standard
IEEE Recommended Practice for Establishing Transformer Capability When Supplying Nonsinusoidal Load Currents
ii
Foreword
(This Foreword is not a part of ANSI/IEEE C57.110-1986, IEEE Recommended Practice for Establishing Transformer Capability When Supplying Nonsinusoidal Load Currents.)
© Copyright 1988 by The Institute of Electrical and Electronics Engineers, Inc 345 East 47th Street, New York, NY 10017, USA No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.
IEEE Standards documents are developed within the Technical Committees of the IEEE Societies and the Standards Coordinating Committees of the IEEE Standards Board. Members of the committees serve voluntarily and without compensation. They are not necessarily members of the Institute. The standards developed within IEEE represent a consensus of the broad expertise on the subject within the Institute as well as those activities outside of IEEE that have expressed an interest in participating in the development of the standard. Use of an IEEE Standard is wholly voluntary. The existence of an IEEE Standard does not imply that there are no other ways to produce, test, measure, purchase, market, or provide other goods and services related to the scope of the IEEE Standard. Furthermore, the viewpoint expressed at the time a standard is approved and issued is subject to change brought about through developments in the state of the art and comments received from users of the standard. Every IEEE Standard is subjected to review at least every five years for revision or reaffirmation. When a document is more than five years old and has not been reaffirmed, it is reasonable to conclude that its contents, although still of some value, do not wholly reflect the present state of the art. Users are cautioned to check to determine that they have the latest edition of any IEEE Standard. Comments for revision of IEEE Standards are welcome from any interested party, regardless of membership affiliation with IEEE. Suggestions for changes in documents should be in the form of a proposed change of text, together with appropriate supporting comments. Interpretations: Occasionally questions may arise regarding the meaning of portions of standards as they relate to specific applications. When the need for interpretations is brought to the attention of IEEE, the Institute will initiate action to prepare appropriate responses. Since IEEE Standards represent a consensus of all concerned interests, it is important to ensure that any interpretation has also received the concurrence of a balance of interests. For this reason IEEE and the members of its technical committees are not able to provide an instant response to interpretation requests except in those cases where the matter has previously received formal consideration. Comments on standards and requests for interpretations should be addressed to: Secretary, IEEE Standards Board 345 East 47th Street New York, NY 10017 USA IEEE Standards documents are adopted by the Institute of Electrical and Electronics Engineers without regard to whether their adoption may involve patents on articles, materials, or processes. Such adoption does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the standards documents.
全系列三极管应用参数

全系列三极管应用参数

全系列三极管应用参数全系列三极管应用参数名称封装极性功耐压电流功率频率配对管D633 28 NPN 音频功放 100V 7A 40W 达林顿9013 21 NPN 低频放大 50V 0.5A 0.625W 90129014 21 NPN 低噪放大 50V 0.1A 0.4W 150HMZ90159015 21 PNP 低噪放大 50V 0.1A 0.4W 150MHZ90149018 21 NPN 高频放大 30V 0.05A 0.4W 1000MHZ8050 21 NPN 高频放大 40V 1.5A 1W 100MHZ85508550 21 PNP 高频放大 40V 1.5A 1W 100MHZ80502N2222 21 NPN 通用 60V 0.8A 0.5W 25／200NS 2N2369 4A NPN 开关 40V 0.5A 0.3W 800MHZ2N2907 4A NPN 通用 60V 0.6A 0.4W 26／70NS2N3055 12 NPN 功率放大 100V 15A 115W MJ29552N3440 6 NPN 视放开 450V 1A 1W 15MHZ2N66092N3773 12 NPN 音频功放 160V 16A 50W2N3904 21E NPN 通用 60V 0.2A2N2906 21C PNP 通用 40V 0.2A2N2222A 21铁 NPN 高频放大 75V 0.6A 0.625W 300MHZ2N6718 21铁 NPN 音频功放 100V 2A 2W2N5401 21 PNP 视频放大 160V 0.6A 0.625W 100MHZ2N55512N5551 21 NPN 视频放大 160V 0.6A 0.625W 100MHZ2N54012N5685 12 NPN 音频功放 60V 50A 300W2N6277 12 NPN 功放开 180V 50A 250W9012 21 PNP 低频放大 50V 0.5A 0.625W 90132N6678 12 NPN 音频功放 650V 15A 175W 15MHZ9012 贴片 PNP 低频放大 50V 0.5A 0.625W 90133DA87A 6 NPN 视频放大 100V 0.1A 1W3DG6B 6 NPN 通用 20V 0.02A 0.1W 150MHZ3DG6C 6 NPN 通用 25V 0.02A 0.1W 250MHZ3DG6D 6 NPN 通用 30V 0.02A 0.1W 150MHZMPSA42 21E NPN 电话视频 300V 0.5A 0.625W MPSA92MPSA92 21E PNP 电话视频 300V 0.5A 0.625W MPSA42MPS2222A 21 NPN 高频放大 75V 0.6A 0.625W 300MHZ9013 贴片 NPN 低频放大 50V 0.5A 0.625W 90123DK2B 7 NPN 开关 30V 0.03A 0.2W3DD15D 12 NPN 电源开关 300V 5A 50W3DD102C 12 NPN 电源开关 300V 5A 50W3522V 5V稳压管A634 28E PNP 音频功放 40V 2A 10WA708 6 PNP 音频开关 80V 0.7A 0.8WA715C 29 PNP 音频功放 35V 2.5A 10W 160MHZA733 21 PNP 通用 50V 0.1A 180MHZA741 4 PNP 开关 20V 0.1A 70／120NSA781 39B PNP 开关 20V 0.2A 80／160NSA928 ECB PNP 通用 20V 1A 0.25WA933 21 PNP 通用 50V 0.1A 140MHZA940 28 PNP 音频功放 150V 1.5A 25W 4MHZ C2073A966 21 PNP 音频激励 30V 1.5A 0.9W 100MHZC2236A950 21 PNP 通用 30V 0.8A 0.6WA968 28 PNP 音频功放 160V 1.5A 25W 100MHZC2238A1009 BCE PNP 功放开关 350V 2A 15WA1220P 29 PNP 音频功放 120V 1.5A 20W 150MHZA1013 21 PNP 视频放大 160V 1A 0.9W C2383 A1015 21 PNP 通用 60V 0.1A 0.4W 8MHZ C18152N6050 12 PNP 音频功放 60V 12A 150W2N6051 12 PNP 音频功放 80V 12A 150WA1175 PNP 通用 60V 0.10A 0.25W 180MHZA1213 贴片 PNP 超高频 50V 0.15A 80MHZA719 ECB PNP 通用 30V 0.50A 0.625W 200MHZB12 G－PNP 音频 30V 0.05A 0.05WB1114 ECB PNP 通用贴 20V 2A 180MHZB205 锗管 PNP 音频功放 80V 20A 80WB1215 BCE PNP 功放开关 120V 3A 20W 130MHZC294 6 NPN 栾生对管 25V 0.05A 200MHZC1044 6 NPN 视放 45V 0.3A 2.2GHZC1216 6 NPN 高速开关 40V 0.2A T，20ｎSC1344 ECB NPN 通用低噪 30V 0.10 230MHZC1733 6 NPN 栾生对管 30V 0.05A 2GHZC1317 21ECB NPN 通用 30V 0.5A 0.625W 200MHZC546 21ECB NPN 高放 30V 0.03A 0.15W 600MHZC680 11 NPN 音频功放 200V 2A 30W 20MHZC665 12 NPN 音频功放 125V 5A 50W 15MHZC4581 BCE NPN 电源开关 600V 10A 65W 20MHZC4584 BCE NPN 电源开关 1200V 6A 65W 20MHZC4897 BCE NPN 行管 1500V 20A 150WC4928 BCE NPN 行管 1500V 15A 150WC5411 BCE NPN 彩显行管1 1500V 14A 60WHQ1F3P 贴片 NPN 功放开关 20V 2A 2WTIP132 28 NPN 音频功放 100V 8A 70W TIP137 A1020 21 PNP 音频开 50V 2A 0.9WA1123 21 PNP 低噪放大 150V 0.05A 0.75WA1162 21D PNP 通用贴 50V 0.15A 0.15WA1216 BCE PNP 功放开关 180V 17A 200W 20MHZC2922A1265 BCE PNP 功放开关 140V 10A 100W 30MHZC3182A1295 BCE PNP 功放开关 230V 17A 200W 30MHZC3264A1301 BCE PNP 功放开关 160V 12A 120W 30MHZC3280C3280 BCE NPN 功放开关 160V 12A 120W 30MHZA1301A1302 BCE PNP 功放开关 200V 15A 120W 30MHZC3281C3281 BCE NPN 功放开关 200V 15A 120W 30MHZA1302A1358 BCE PNP 120V 1A10W 120MHZA1444 BCE PNP 高速电源 100V 15A 30W 80MHZA1494 BCE PNP 功放开关 200V 17A 200W 20MHZC3858A1516 BCE PNP 功放开关 180V 12A 130W 25MHZA1668 BCE PNP 电源开关 200V 2A 25W 20MHZA1785 BCE PNP 驱动 120V 1A 1W 140MHZA1941 BCE PNP 音频功放 140V 10A 100W C5198 C5198 BCE NPN 音频功放 140V 10A 100W A1941 A1943 BCE PNP 功放开关 230V 15AA 150W C520C5200 BCE NPN 功放开关 230V 15A 150W A1943A1988 BCE PNP 功放开关B449 锗 12 PNP 功放开关 50V 3.5A 22.5WB647 21 PNP 通用 120V 1A 0.9W 140MHZD667D667 21 NPN 通用 120V 1A 0.9W 140MHZB649B1375 BCE PNP 音频功放 60V 3A 2W 9MHZD40C BCE NPN对讲机用40V 0.5A 40W 75MHB688 BCE PNP 音频功放 120V 8A 80W D718 B734 39B PNP 通用 60V 1A 1W D774 B649 29 PNP 视放 180V 1.5A 20W D669D669 29 NPN 视频放大 180V 1.5A 20W 140MHZB649B669 28 PNP 达林顿功 70V 4A 40WB675 28 PNP 达林顿功 60V 7A 40WB673 28 PNP 达林顿功 100V 7A 40WB631K 29 PNP 音频功放 120V 1A 8W 130MHZD600KD600K 29 NPN 音频功放 120V 1A 8W 130MHZB631KC3783 BCE NPN 高压高速 900V 5A 100WB1400 28B PNP 达林顿功 120V 6A 25W D1590 B744 29 PNP 音频功放 70V 3A 10WB1020 28 PNP 功放开关 100V 7A 40WB1240 39B PNP 功放开 40V 2A 1W 100MHZB1185 28B PNP 功放开 60V 3A 25W 70MHZD1762B1079 30 PNP 达林顿功 100V 20A 100W D1559B772 29 PNP 音频功放 40V 3A 10W D882 B774 21 PNP 通用 30V 0.1A 0.25WB817 30 PNP 音频功放 160V 12A 100W D1047 B834 28 PNP 功放开关 60V 3A 30WB1316 54B PNP 达林顿功 100V 2A 10WB1317 BCE PNP 音频功放 180V 15A 150W D1975B1494 BCE PNP 达林顿功 120V 20A 120W D2256 B1429 BCE PNP 功放开关 180V 15A 150WC380 21 NPN 高频放大 35V 0.03A 250MHZC458 21 NPN 通用 30V 0.1A 230MHZC536 21 NPN 通用 40V 0.1A 180MHZ2N6609 12 PNP 音频功放 160V 15A 150W ＞2MHZ 2N3773C3795 BCE NPN 高压高速 900V 5A 40WC2458 21ECB NPN 通用低噪 50V 0.15A 0.2WC3030 BCE NPN 开关管 900V 7A 80W. 达林顿C3807 BCE NPN 低噪放大 30V 2A 1.2W 260MHZC3858 BCE NPN 功放开关 200V 17A 200W 20MHZA1494D985 29 NPN 达林顿功 150V ±1.5A 10WC2036 29 NPN 高放低噪 80V 1A 1－4WC2068 28E NPN 视频放大 300V 0.05A 1.5W 80MHZC2073 28 NPN 功率放大 150V 1.5A 25W 4MHZ A940C3039 28 NPN 电源开关 500V 7A 50WC3058 12 NPN 开关管 600V 30A 200WC3148 28 NPN 电源开关 900V 3A 40WC3150 28 NPN 电源开关 900V 3A 50WC3153 30 NPN 电源开关 900V 6A 100WC3182 30 NPN 功放开关 140V 10A 100W A1265C3198 21 NPN 高频放大 60V 0.15A 0.4W 130MHZ3DK4B 7 NPN 开关 40V 0.8A 0.8W3DK7C 7 NPN 开关 25V 0.05A 0.3W3D15D 12 NPN 电源开关 300V 5A 50WC2078 28 NPN 音频功放 80V 3A 10W 150MHZC2120 21 NPN 通用 30V 0.8A 0.6WC2228 21 NPN 视频放大 160V 0.05A 0.75WC2230 21 NPN 视频放大 200V 0.1A 0.8WC2233 28 NPN 音频功放 200V 4A 40WC2236 21 NPN 通用 30V 1.5A 0.9W A966C1733 小铁 NPN 孪生对管 30V 2GHZC1317 21EBC NPN 通用 30V 0.5A 0.625W 200MHZC2238 28 NPN 音频功放 160V 1.5A 25W 100MHZA968C752 21 NPN 通用 30V 0.1A 300MHZC815 21 NPN 通用 60V 0.2A 0.25WC828 21 NPN 通用 45V 0.05A 0.25WC900 21 NPN 低噪放大 30V 0.03A 100MHZC945 21 NPN 通用 50V 0.1A 0.5W 250MHZC1008 21 NPN 通用 80V 0.7A 0.8W 50MHZC1162 21 NPN 音频功放 35V 1.5A 10WC1213 39B NPN 监视器专 30V 0.5A 0.4WC1222 21 NPN 低噪放大 60V 0.1A 100MHZC1494 40A NPN 发射 36V 6A PQ=40W 175MHZ C1507 28 NPN 视放 300V 0.2A 15WC1674 21 NPN HF/ZF 30V0.02A 600MHZC1815 21 NPN 通用 60V 0.15A 0.4W 8MHZA1015C1855 21F NPN HF/ZF 20V0.02A 550MHZC1875 12 NPN 彩行 1500V 3.5A 50WC1906 21 NPN 高频放大 30V 0.05A 1000MHZC1942 12 NPN 彩行 1500V 3A 50WC1959 21 NPN 通用 30V 0.4A 0.5W 300MHZC1970 28 NPN 手机发射 40V 0.6A PQ=1.3W 175MHZC1971 28A NPN 手机发射 35V 2A PQ-7.0W 175MHZC1972 28A NPN 手机发射 35V 3.5A PQ=15W 175MHZC2320 21 NPN 通用 50V 0.2A 0.3W 200MHZC2012 21 NPN 高放 30V 0.03A 200MHZC2027 12 NPN 行管 1500V 5A 50WD814 BCE NPN 低噪放大 150V 0.05A 150MHZC5142 BCE NPN 彩行 1500V 20A 200WD998 BCE NPN 音频功放 120V 10A 80W <1/3USD2253 BCE NPN 彩显行管 1700V 6A 50WD110 12 NPN 音频功放 130V 10A 100W 1MHZC2335 28 NPN 视频功 500V 7A 40WC2373 28 NPN 功放 200V 7.5A 40WC2383 21 NPN 视频开关 160V 1A 0.9W A1013 C3300 30 NPN 音频功放 100V 15A 100WC3310 28C NPN 电源开关 500V 5A 40WC3320 28C NPN 电源开头 500V 15A 80WC3355 21F NPN 高频放大 20V 0.1A 6500MHZC3358 40B NPN 高频放大 20V 0.1A 7000MHZC3457 BCE NPN 电源开关 1100V 3A 50WC3460 BCE NPN 电源开关 1100V 6A 100WC3466 BCE NPN 电源开关 1200V 8A 120WC3505 28B NPN 电源开关 900V 6A 80WC3527 BCE NPN 电源开关 500V 15A 100WC3528 BCE NPN 电源开关 500V 20A 150WC3866 BCE NPN 高压高速 900V 3A 40WC2443 大铁 NPN 功放开关 600V 50A 400WC2481 29 NPN 音频功放 150V 1.5A 20WC2482 21 NPN 视频放大 300V 0.1A 0.9WC2500 21 NPN 通用 30V 2A 0.9W 150MHZC2594 29 NPN 音频功放 40V 5A 10WC2611 29 NPN 视频放大 300V 0.1A 1.25WC2625 30 NPN 音频功放 450V 10A 80WC2682 29 NPN NF/Vid 180V0.1A 8WC2688 29 NPN 视放管 300V 0.2A 10W 80MHZC2690 29 NPN 音频功放 120V 1.2A 20W 150MHZA1220PC2751 BCE NPN 电源开关 500V 15A 120WC2837 30 NPN 音频功放 150V 10A 100WC3873 BCE NPN 高压高速 500V 12A 75W 30MHZC3886 BCE NPN 开关行 1400V 8A 50W 8MHZC3893 28B NPN 行管 1400V 8A 50W 8MHZC3907 28B NPN 功放开关 180V 12A 130W 30MHZC3595 29 NPN 射频 30V 0.5A 1.2WC4059 BCE NPN 高速开关 600V 15V 130W 0.5/2.2US C4106 BCE NPN 电源开关 500V 7A 50W 20MHZ?C4111 BCE NPN 开关行 1500V 10A 150WC3679 BCE NPN 电源开关 900V 5A 100W 6MHZC2898 28 NPN 音频功放 500V 8A 50WC2922 43 NPN 音频功放 180V 17A 200W 50MHZA1216C3026 12 NPN 开关管 1700V 5A 50WD986 29 NPN 达林顿功 150-80V ±1.5A 10WC3262 BCE NPN 功放 800V 10A 100WC3264 BCE NPN ＰＡ功放 230V 17A 200WB=170 A1295 C3280 30 NPN 音频功放 160V 12A 120WB=100C3281 30 NPN 音频功放 200V 15A 150W 30MHZC3680 BCE NPN 电源开关 900V 7A 120W 6MHZC3688 BCE NPN 彩行 1500V 10A 150WC3720 12 NPN 彩行 1200V 10A 200WC3953 29 NPN 视放 120V 0.2A 1.3W 400MHZC3987 28 NPN 达林顿 50V 3A 20WC3995 BCE NPN 行管 1500V 12A 180WD1025 28 NPN 达林顿功 200V 8A 50WC3997 BCE NPN 行管 1500V 15A 250WC3998 BCE NPN 行管 1500V 25A 250WC4024 BCE NPN 功放开关 100V 10A 35W 24MHZC4038 BCE NPN 门电路 50V 0.1A 0.3W 180MHZ D1037 BCE NPN 音频功放 150V 30A 180WD1047 30 NPN 音频功放 160V 12A 100W B817C4119 BCE NPN 微波炉 1500V 15A 250WC4231 50C NPN 音频功放 800V 2A 30WC4237 BCE NPN 高压高速 1000V 8A 120W 30MHZC4242 BCE NPN 高压高速 450V 7A 40WC4297 BCE NPN 电源开关 500V 12A 75W 10MHZC4429 BCE NPN 电源开关 1100V 8A 60WC4517 BCE NPN 音频功放 550V 3A 30W 6MHZC4532 BCE NPN 大屏行管 1700V 10A 200WC4582 BCE NPN 电源开关 600V 15A 75W 20MHZON4673 BCE NPNON4873 BCE NPNC5244 BCE NPN 彩行 1700V 15A 200WC5249 BCE NPN 功放开关 600V 3A 35W 6MHZC5250 BCE NPN 开关 1000V 7A 100WC5251 BCE NPN 彩行 1500V 12A 50WD1071 28 NPN 达林顿功 300V 6A 40WC4706 BCE NPN 电源开关 900V 14A 130W 6MHZC4382 BCE NPN 功放开关 200V 2A 25W 20MHZ A1668C4742 46 NPN 彩行 1500V 6A 50WC4745 46 NPN 彩行 1500V 6A 50WC4747 46 NPN 彩行 1500V 10A 50WC4769 BCE NPN 微机行管 1500V 7A 60WC4913 BCE NPN 大屏视放 2000V 0.02A 35WC4924 BCE NPN 音频功放 800V 10A 70WC4927 BCE NPN 行管 1500V 8A 50WC4927 BCE NPN SONY29行 1500V 8A 50WC4941 BCE NPN 行管 1500V 6A 65W 500/380NS C4953 BCE NPN 功放开关 500V 2A 25W t=300nSC5020 BCE NPN 彩行 1000V 7A 100WC5068 BCE NPN 彩行 1500V 10A 50WC5086 BCE NPN 彩行 1500V 10A 50WC5088 BCE NPN 彩行 1500V 10A 50WC5129 BCE NPN 彩显行管 1500V 8A 50WD1163A 28 NPN 行偏转用 350V 7A 40W 60MHZD1175 12 NPN 行偏转用 1500V 5A 100WC5132 BCE NPN 彩行 1500V 16A 50WC5144 BCE NPN 大屏彩行 1700V 20A 200WC5148 BCE NPN 大屏彩行 1500V 8A 50WC5149 BCE NPN 高速高频 1500V 8A 50WC5198 BCE NPN 功放开关 140V 10A 100WC5200 BCE NPN 功放开关 230V 15A 150W A1943 D1273 28 NPN 音频功放 80V 3A 40W 50MHZC5207 BCE NPN 彩行 1500V 10A 50WC5243 BCE NPN 彩行 1700V 15A 200WC5252 BCE NPN 彩行 1500V 15A 100WC5294 BCE NPN 彩行 1500V 20A ｔ＝200MSC5296 BCE NPN 开关管 1500V 8A 80WC5297 BCE NPN 开关管 1500V 16A 60WC5331 BCE NPN 大屏彩显 1500V 15A 180WD325 BCE NPN 功放开关 50V 3A 25WD385 11 NPN 达林顿功 100V 7A 30WD400 21 NPN 通用 25V 1A 0.75WD1302 21 NPN 音频 25V 0.5A 0.5W 200MHZD1397 BCE NPN 开关 1500V 3.5A 50W 3MHZD1398 BCE NPN 开关 1500V 5A 50W 3MHZD1403 BCE NPN 彩行 1500V 6A 120WD401 28 NPN 音频功放 200V 2A 20WD415 29 NPN 音频功放 120V 0.8A 5WD438 21 NPN 通用 500V 1A 0.75W 100MHZD560 BCE NPN 达林顿功 150V 5A 30WD637 39E NPN 通用 60V 0.1A 150MHZD667 21 NPN 视频放大 120V 1A 0.9W 140MHZB647D1403 BCE NPN 彩行 1500V 6A 120WD1415 BCE NPN 功放电源 100V 7A 40W 达林顿D718 30 NPN 音频功放 120V 8A 80W B668 D774 39B NPN 通用 100V 1A 1W B734 D789 21 NPN 音频输出 100V 1A 0.90D820 12 NPN 彩行 1500V 5A 50WD870 12 NPN 彩行 1500V 5A 50WD880 28 NPN 音频功放 60V 3A 10WD882 29 NPN 音频功放 40V 3A 30W B772 D884 28 NPN 音频功放 330V 7A 40WD898 12 NPN 彩行 1500V 3A 50WD951 12 NPN 彩行 1500V 3A 65WD965 21 NPN 音频 40V 5A 0.75WD966 21 NPN 音频 40V 5A 1WD633拆 28 NPN 音频功放 100V 7A 40W达林顿D1431 28B NPN 彩行 1500V 5A 80WD1433 28B NPN 彩行 1500V 7A 80WD1980 61B NPN 达林顿 100V 2A 10WD1981 EBC NPN 达林顿 100V 2A 1WD1993 45B NPN 音频低噪 55V 0.1A 0.4WD1416 BCE NPN 功放电源 80V 7A 40W 达林顿D1427 BCE NPN 彩行 1500V 5A 80W 带阻尼BU2525AF 30 NPN 开关功放 1500V 12A 150W 350NSD1428 28B NPN 彩行 1500V 6A 80W 带阻尼BU2525AX 30 NPN 开关功放 1500V 12A 150W 350NSD1439 BCE NPN 彩行 1500V 3A 80WD1541 28B NPN 彩行 1500V 3A 80WD1545 28B NPN 彩行 1500V 5A 50WD1547 BCE NPN 彩行 1500V 7A 80WBU2527AF 30 NPN 开关功放 1500V 15A 150WD1554 BCE NPN 彩行 1500V 3.5A 80WD1555 BCE NPN 彩行 1500V 5A 80WD1556 BCE NPN 彩行 1500V 6A 80WD1559 BCE NPN 达林顿功 100V 20A 100W B1079 D1590 28 NPN 达林顿功 150V 8A 25WD1623 28B NPN 彩行 1500V 4A 70WD1640 29 NPN 达林顿功 120V 2A 1.2WD1651 SP NPN 彩行 1500V 5A 60W 3MHZD1710 BCE NPN 彩行 1500V 5A 50WD1718 28C NPN 音频功放 180V 15A 150W 20MHZD1762 BCE NPN 音频功放 60V 3A 25W 90MHZ B1185D1843 BCE NPN 低噪 50V 1A 1WD1849 50A NPN 彩行 1500V 7A 120WD1850 50A NPN 彩行 1500V 7A 120WD1859 50A NPN 音频 80V 0.7A 1W 120MHZD1863 50A NPN 音频 120V 1A 1W 100MHZD1724 29 NPN 开关 120V 3A 180MHZD1877 30 NPN 彩行 1500V 4A 50W 带阻尼D1879 30 NPN 彩行 1500V 6A 60W 带阻尼D1887 20 NPN 彩行 1500V 10 70WD1930 21 NPN 达林顿 100V 2A 1.2W 达林顿D1975 53A NPN 音频功放 180V 15A 150W B1317BU2532AW 30 NPN 开关功放 1500V 15A 150WD1978 21 NPN 达林顿 120V 1.5A 0.9WD1994A EBC NPN 音频驱动 60V 1A 1WBD237 29 NPN 音频功 100V 2A 25W BD238BD238 29 PNP 音频功 100V 2A 25W BD237BU2520AF 30 NPN 开关功放 1500V 10A 150W 1/500NSBU2520DF 30 NPN 开关功放 1500V 10A 150W 1/500NSBU2520DX 30 NPN 开关功放 1500V 10A 50W 600NSBUH515 BCE NPN 行管 1500V 10A 80WBUH515D BCE NPN 行管 1500V 10A 80WBUS13A 12 NPN 开关功放 1000V 15A 175WD1997 45B NPN 激励管 40V 3A 1.5W 100MHZD2008 EBC NPN 音频功放 80V 1A 1.2WD2012 BCE NPN 音频功放 60V 3A 2W 3MHZD2136 EBC NPN 功放 80V 1A 1.2WD2155 53A NPN 音频功放 180V 15A 150WD2256 46 NPN 达林顿功 120V 25A 125W B1494 D2334 28B NPN 彩行 1500V 5A 80WD2335 BCE NPN 彩行 1500V 7A 100W 带阻尼D2349 BCE NPN 大屏彩显 1500V ±10A 50WD1959 BCE NPN 彩行 1400V 10A 50WD2374 BCE NPN 功放开关 60V 3A 25W 30MHZD2375 BCE NPN 高放大倍 80V 3A 25W 50MHZD2388 EBC NPN 达林顿 90V 3A 1.2WD2445 BCE NPN 彩行 1500V 12.5A 120WD2498 BCE NPN 彩行 1500V 6A 50WD2588 BCE NPN 点火器用DK55 BCE NPN 开关 400V 4A 60WBC307 21a PNP 通用 50V 0.2A 0.3WBC327 CBE PNP 低噪音 50V 0.8A 0.625WBC337BC337 21a NPN 音频激励 50V 0.8A 0.625W BC327BC338 21a NPN 通用激 50V 0.8A 0.6WBC546 21a NPN 通用 80V 0.2A 0.5WBC547 CBE NPN 通用 50V 0.2A 0.5W 300MHZBD135 29 NPN 音频功 45V 1.5A 12.5WBD136 29 PNP 音频功 45V 1.5A 12.5WBD137BD137 29 NPN 音频功 60V 1.5A 12.5WBD136频功 60V 1.5A 12.5WBD139BD139 29 PNP 音频功 80V 1.5A 12.5WBD138BUS14A 12 NPN 开关功放 1000V 30A 250WBUT11A 28 NPN 开关功放 1000V 5A 100WBD243 28 NPN 音频功 45V 6A 65W BD244BD244 28 PNP 音频功 45V 6A 65W BD243BD681 29 NPN 达林顿功 100V 4A 40W BD682 BD682 29 PNP 达林顿功 100V 4A 40W BD681 BF458 29 NPN 视放 250V 0.1A 10WBU208A 12 NPN 彩行 1500V 5A 12.5WBU208D 12 NPN 彩行 1500V 5A 12.5WBU323 28 NPN 达林顿功 450V 10A 125WBU406 28 NPN 行管 400V 7A 60WBU508A 28 NPN 行管 1500V 7.5A 75WBU508A 28 NPN 行管 1500V 7.5A 75WBU508D 28 NPN 行管 1500V 7.5A 75W放 400V 8A 60WBU932R 12 NPN 功放 500V 15A 150WBUT12A 28 NPN 开关功放 450V 10A 125WBU941 12 NPN 功放开关 500V 15A 175W 达林顿BU1508DX 28 NPN 开关功放 1500V 8A 35WBU2506DX 30 NPN 开关功放 1500V 7A 50W 600NSBU2508AF 30 NPN 开关功放 1500V 8A 125W 600NSBU2508AX 30 NPN 开关功放 1500V 8A 125W 600NSBU2508DF 30 NPN 开关功放 1500V 8A 125W 600NSBU2508DX 30 NPN 开关功放 1500V 8A 50W 600NSBUV26 28 NPN 音频功放 90V 14A 65W 250NSBU2522AF 30 NPN 开关功放 1500V 11A 150W 350NSMJ15024 12 NPN 音频功放400V 16A 250W 4MHZMJ15025MJ15025 12 PNP 音频功放 400V 16A 250W 4MHZ MJ15024MJE271 29 PNP 达林顿 100V 2A 15W 6MHZBUV28A 28 NPN 音频功放 225V 10A 65W 250NS放 450V 15A 150WBUW13A 30 NPN 功放开关 1000V 15A 150WBUX48 12 NPN 功放开关 850V 15A 125WBUX84 30 NPN 功放开关 800V 2A 40WBUX98A 12 NPN 功放开关 400V 30A 210W 5MHZDK55 28 NPN 功放开关 400V 4A 65WDTA114 PNP 10K－10K 160V 0.6A 0.625WDTC143 NPN 录像机用 4.7kHPA100 BCE NPN 大屏彩显 1500V 10A 150WHPA150 BCE NPN 大屏彩显 1500V 15A 150WHSE830 BCE PNP 音频功放 80V 115W 1MHZ HSE80HSE838 BCE NPN 音频功放 80V 115W 1MHZ HSE83MN650 BCE NPN 行管 1500V 6A 80WMJ802 12 NPN 音频功放 90V 30A 200W MJ4502 MJ2955 12 PNP 音频功放 60V 15A 115W MJ3055MJ3055 12 NPN 音频功放 60V 15A 115W MJ2955放 90V 30A 200W MJ802MJ10012 12 NPN 达林顿 400V 10A 175WMJ10015 12 NPN 电源开关 400V 50A 200WMJ10016 12 NPN 电源开关 500V 50A 200WMJ10025 12 电源开关 850V 20A 250WMJ11032 12 NPN 电源开关 120V 50A 300W MJ11033MJ11033 12 PNP 电源开关 120V 50A 300W MJ11032MJ13333 12 NPN 电源开关 400V 20A 175WMJ11015 12 PNP 铁达林顿 500V 10AMJ14003 12 PNP 铁MJE340 29 NPN 视放 300V 0.5A 20W MJE35MJE350 29 PNP 视放 300V 0.5A 20W MJE34MJE2955T BCE PNP 音频功放 60V 10A 75W 2MHZ MJE3055TMJE3055T BCE NPN 音频功放 70V 10A 75W 2MHZ MJE2955TMJE5822 BCE PNP 音频功放 500V 8A 80WMJE9730 BCE NPNMJE13003 29 NPN 功放开关 400V 1.5A 14WMJE13005 28 NPN 功放开关 400V 4A 60WMJE13007 28 NPN 功放开关 1500V 2.5A 60WKSE800 28 NPN 达林顿 140V 4A 20WTIP31C BCE NPN 功放开关 100V 3A 40W 3MHZ TIP32TIP32C BCE PNP 功放开关 100V 3A 40W 3MHZ TIP31TIP35C 30 NPN 音频功放 100V 25A 125W 3MHZ TIP36TIP36C 30 PNP 音频功放 100V 25A 125W 3MHZ TIP35TIP41C 30 NPN 音频功放 100V 6A 65W 3MHZ TIP42TIP42C 30 PNP 音频功放 100V 6A 65W 3MHZ TIP41TIP102 28 NPN 音频功放 100V 8A 2WTIP105 28 PNP 音频功放 60V 15A 80W 达林顿TIP122 28 NPN 音频功放 100V 5A 65W TIP127 TIP127 28 PNP 音频功放 100V 5A 65W TIP122 TIP137 28 PNP 音频功放 100V 8A 70W TIP132 TIP142 30 NPN 音频功放 100V 10A 125W TIP147TIP142大 30 NPN 音频功放 100V 10A 125W TIP147TIP147 30 PNP 音频功放 100V 10A 125W TIP142TIP147大 30 PNP 音频功放 100V 10A 125W TIP142TIP152 BCE 电梯用达 400V 3A 65WTL431 21 电压基准源BT33 电压结晶体管UGN3144 SGO 霍尔开关60MIAL1 电磁／微 1000V 60A 300WT30G40 BCE NPN 大功率开 400V 30A 300W5609 21 NPN 音频低频 50V 0.8A 0.625W 5615610 21 PNP 音频低频 50V 0.8A 0.625W 5619626 21 NPN 通用收藏分享。

风险管理与金融机构课后附加题参考答案(中文版)

风险管理与金融机构课后附加题参考答案(中文版)

风险管理与金融机构第四版约翰·C·赫尔附加问题(Further Problems)的答案第一章:导论1.15.假设一项投资的平均回报率为8%，标准差为14%。

另一项投资的平均回报率为12%，标准差为20%。

收益率之间的相关性为0.3。

制作一张类似于图1.2的图表，显示两项投资的其他风险回报组合。

答：第一次投资w1和第二次投资w2=1-w1的影响见下表。

可能的风险回报权衡范围如下图所示。

w1 w2μp σp0.0 1.0 12% 20%0.2 0.8 11.2% 17.05%0.4 0.6 10.4% 14.69%0.6 0.4 9.6% 13.22%0.8 0.2 8.8% 12.97%1.0 0.0 8.0% 14.00%1.16.市场预期收益率为12%，无风险收益率为7%。

市场收益率的标准差为15%。

一个投资者在有效前沿创建一个投资组合，预期回报率为10%。

另一个是在有效边界上创建一个投资组合，预期回报率为20%。

两个投资组合的回报率的标准差是多少？答：在这种情况下，有效边界如下图所示。

预期回报率为10%时，回报率的标准差为9%。

与20%的预期回报率相对应的回报率标准差为39%。

1.17.一家银行估计, 其明年利润正态分布, 平均为资产的0.8%，标准差为资产的2%。

公司需要多少股本（占资产的百分比）：（a）99%确定其在年底拥有正股本；（b）99.9%确定其在年底拥有正股本？忽略税收。

答：（一）银行可以99%确定利润将优于资产的0.8-2.33×2或-3.85%。

因此，它需要相当于资产3.85%的权益，才能99%确定它在年底的权益为正。

（二）银行可以99.9%确定利润将大于资产的0.8-3.09×2或-5.38%。

因此，它需要权益等于资产的5.38%，才能99.9%确定它在年底将拥有正权益。

1.18.投资组合经理维持了一个积极管理的投资组合，beta值为0.2。