电子电路外文文献

1、电子电路外文文献外文原文From CHARLES A(HOLT . ELECTRONIC CIRCUITS Digital and Analog.1. 1 Basic amplifierStudies the amplifier, we first analyze the circuit of the chart 121, it contains abias in the enlargement area NPN transistor. Although base sector width W is the collector voltage function, but in order to

2、 cause the discussion to simplify as far as possible, will neglect this secondary effect. Therefore, I and aregard as the ESFconstant. MarkIn here as well as in entire this book, uses the standard symbolic representation electric current and the voltage. The electric current is i is i=I+i BBBb(12-1)

3、When Vfor zero, chart 121 electric circuit is called the static state, namely is at ithe dormant state, the static base current is I:when V is not the zero, difference of Bijoint current i and the quiescent value is i. Mark i expresses the increase electric Bbbcurrent, also is called i signal compon

4、ent. Attention: i, I, ithe custom bB B breference direction take flows in the component the B end as.Vexpression from base extremely B to emitter electrode E loss of voltage, BEsimilarly wrote it quiescent voltage V and sum of the increase voltage V. Chart in BEbe121 electric circuit V is V. In brie

5、f, the lowercase letter raises writes the subscript beito express various joint currents and the total voltage： The capital letter raises writes the subscript to express various static quantity：The lowercase letter belt small letter subscript uses in various increases variable. Stated not specially

6、that, the electric current reference direction take flows in the component as. The voltage reference direction uses the double subscript, when or attempts in likely 121 Vo such with thepositive and negative symbolic representation, then Q voltage andthe electric current refer to the static quantity.

7、忆匸卩0+斗Chart 1. 1 the amplifier14th chapter operational amplifierExcept that preceding flees has discussed altogether shoots, altogether the collection and altogether outside the base electric circuit, but also has another kind of specially important basic configuration, this is the differential ampl

8、ifier. It has two signal voltage to input Swiss and an in proportion to input signal interpolation output. Frequently, from provides the negative feedback in the bleeder network to withdraw the output a part of achievement input voltage： But sometimes, an input end sweet and crisp earth. In these tw

9、o kinds of situations, the differential amplifier all turns only then an input and an output single end amplifier.We will see to, the differential amplifier might process the big signal but not to have the oversized nonlinear distortion, moreover this big dynamic range will be one of its multitudino

10、us characteristics.Because bias not big time input impedance for center to high impedance, therefore the supply oscillator load cannot be overweight. In the low frequency work (including direct current) is possible. Its electric circuit structure suits the sub-integrated circuit manufacture speciall

11、y, thus the most linear integrated circuit contains level or the multistage differential amplifier. This kind of electric circuit example includes:The analog computer network, the monolithic voltage - stabilizer, the video amplifier, simulate the comparator and the operational amplifier.And followin

12、g several deaf center enlarges in this chapter the operation 2E multi-purpose and the versatility does the key point is correct.The operational amplifier is has the difference input level the multistage structure, its characteristic for the voltage gain big, the input impedance high and the output i

13、mpedance is low. It widely uses in many different types linearity and in the nonlinear circuit. Using involves to the measuring appliance electric circuit, the special use linear amplifier, the oscillator, has the clothing filter and other electric circuits. In fact, every request is inexpensive vol

14、tage amplification situation, all should consider uses the operational amplifier.This chapter studies the operational amplifier some basic characteristics, certain applications also including. Other questions then proposed in the following several chapters. Shows in 15 chapter and in 17 chapter and

15、succinctly discusses three kind of different operational amplifiers the electric circuit, let us from the differential amplifier start study.2 Differential amplifierEmitter coupling amplifierHas each kind of type the differential amplifier. The common electric circuit structure is arranges two BJT e

16、mitter electrode the increase series. Solid illustration in chart 141 a. The ideal current supply provides constant direct current Ide in this electric circuit.Therefore, to emitter current increase ingredient ideal current supply for leads the way. Its increase electric circuit has chart 14lb the f

17、orm. In the chart,the ideal direct current potential source and the current supplyhave used to short-circuit and to lead the way separately thesubstitution. Obviously i,-i The ele2amplifier speaking of the increase electric current two emitterelectrodes to connect (like chart 141 b two emitter elect

18、rodes such),is called the emitter coupling amplifier.More importantly transistor Q and Q must pair as far as possible,causes their 12characteristic nearly in to be consistent. When the transistor pairwith the input voltage is a zero hour, two transistors collectingelectrode electric currents are sam

19、e. Comes from the electric circuitsymmetry to see this is obvious. Even if abbreviates the Q collectionelectricity level resistance, two electric currents almost are also 1equal, because works in the enlargement area BJT collectingelectrode electric currenthas nothing to do with nearly with V. There

20、upon, this resistance issometimes CEabbreviated.Retains it s goal to lie in improvement direct currentto be balanced.In the increase model, (its function the resistancewhich just likecurrent supply) connects does not have what influencewith the high impedance collecting electrode.Input end A and B a

21、re Q and the Q base extreme. The increase modelregarding 12amplifier the form,the small signal is linear, may apply the principle of superposition.Therefore, inputs us to two to be possible to process separately. Make V =0, to this kind of situation, S2The increase electriccircuit may draw becomes t

22、he two-polechart 2.1.3 increase modelLike chart 142 show. Just like front had pointed out, the first level of Rc influence may neglect. Obviously this level is approximate is altogether the collection configuration, but second level then is altogether the base. This cascade input impedance is has sa

23、me r and the r value altogether shoots the amplifier input sximpedance two times.So long as the load resistance is smaller than r, in altogether collection and oaltogether in base two kinds of amplifier when to transmission may suddenly bribery resistance r and r. Makes the load by altogether the gr

24、ound level low input u oimpedance altogether the collection level obviously to satisfy this request. Because load resistance Rc is usually actual electric circuit in r to be much smaller than, otherefore the common base also satisfies this request. When V = 0, joins V, the sls2situation is similar.

25、The output voltage then may from no matter what a collecting electrode obtains. In fact, we will see to, in two collecting electrodes resistances increase voltage scope equal but the mark will be opposite. Therefore, the following will analyze neglects with the base sector width modulation related p

26、arameter.When supply oscillator resistance Radds to the electric circuit, among sfrequency band increase model like chart 143 show. Supposes two transistors ispairs, and has the same quiescent point and the increase parameter.Each collecting electrode resistance R and the collecting electrode increa

27、se current supply connects, cTherefore, these resistances do not affect the electric circuit the electric current. Further said, if removes a resistance, does not changein addition in the resistance voltage. Indicates i, i in the emitter electrode pitch point node equation. Obviously, 12two output v

28、oltages scope equal but the mark is opposite.Bad mold voltage gain and altogether mold voltage gainExternal circuits return route equations obtain by chart 2. 1. 2Output voltageV, PRi, Bad mold voltage gain A defines difference of as the ooc2doutput voltageand two input voltages ratio, namely%chart

29、2. 1. 4 among frequency band modelOutputs V is the V negative value. According to 165 center discussion, this kind ooof amplifier may serve as the phase-splitter. Each output all inproportion to two inputs miss VV. This interpolation is called difference mold input voltage V, sls2dnamelyTwo input vo

30、ltages mean value is 1/2, represents altogether mold input voltage V, cThereforeWhen two input voltages are altogether the mold increase by this equal output voltage ratio of with altogether the mold input voltage AcRegarding chart 143 electric circuits, when two input voltages equal output voltage

31、is the zero, thus altogether the mold gain is the zero.So long as application chart 2. 2. 3 simplifications models, even if two transistors do not pair, altogether the mold increases also is az ero.To this kind of situation, may prove the electric current by the node equation: i and i each other has

32、 the direct ratio, 12thus works as two input voltages equal time two electric currents are the zero inevitably. However, if includes base sector width modulation resistance rand r, is o ueasy to prove to transistor which has not paired, usual A is not az ero.Therefore, calthough these resistances in

33、crease tothe difference mold theinfluence may neglect, when calculates A,in the model must include rand r. Chart 143 models co nincluding have not provided the staticstate emitter current theactual power source increase resistance. This resistance very is usuallybig, increases when the determination

34、 difference mold may neglect it.But in determined when A, it is cpossibly important. Even regarding the transistor which pairs, thisresistance appears when the model, all can cause A is not the zero. Whenlow frequency, the A value ccmay be possible negative.Difference of because of the request outpu

35、t in proportion to two inputs, therefore works as two inputs equal time outputs must be minimum.When ideal A should be a cz ero.An important quality factor is altogether the mold rejection ratio (CMRR), it defines as orUses the full symmetry the electric circuit, uses the transistor which pairs and

36、has the very high increase resistance the direct current source, may obtain the big CMRRvalue. Usually, CMRR obtains by the experiment, its value possibly is bigger than 10or 100 dB. By already not CMRR and the A value, may extract altogether the mold dto increase A the size, but cannot determine po

37、sitively and negatively its. c2.Active RC filterThe filter permit or continue a transmission band, at the same time blocks outside these frequency bands the signal. In the low pass filter, the transmission band extends from the zero to some upper frequency.High passes the filter only through to be h

38、igher than some rating the frequency. Also has the band pass filter and the band-elimination filter.Falls the wave filter to filter out a very narrow frequency band, sometimes places it the amplifier in the feedback network by to obtain the narrow band pass filter. The passive filter by the resistan

39、ce, the electric capacity, the inductance is composed, but the active RC filter by the resistance, the electric capacity and the active device are composed. Removes the inductance is the RC filter main merit, it obtains the widespread application and is easy to realize. Passes is commonly used it to

40、 filter needs outside the frequency band the noise. As a result of the operational amplifier frequency restriction, the active filter pass conunonly used below approximately the lOkHz audio frequency scope. Regarding likes 741 that kinds the operational amplifier which has the interior to compensate

41、, is only restricted in has below pass band probably IkHz in the filter to use.Chart 2320 show for the first order low pass filter, because of it only then a simple pole. Passes through this content, supposes the operational amplifier is ideal. Defines the basic feedback amplifier gain K and with it

42、s correlation RC network 3 as 0follows:is not difficult from chart 2320 to extract the voltage gain forchart 2321 two steps low pass filterThe extreme is -3，the zero spot is an infinitely great. The gainin low frequency is K, 0in 3 drops 3dB, when very high-frequency tends to the zero.Thepass band e

43、xtends 0from the zero to3. The RC filter provide with next level ortheload between cushion 0by the operational amplifier, the operational amplifier alsohas thevoltage gain. Incertain applications, chart 2320 operational amplifiers are saved.Chart 2321 two steps low temperatures filter have the incis

44、ivecut-off characteristic. Obtains its gain is3 and K (2312) defines by the type. Needs to choose K to obtainthe suitable 0extreme. Is not difficult to prove: if K (2315) chooses accordingto the type, then type (2314) two extremes are the mold for 3, anglefor 0 conjugate complex 0numbers.Once extrac

45、ted in 212, does not have the peak to get up the most incisive cut-offocharacteristic to occur in the extreme angle was 45 time. (2315) may know fromothe type, must choose 45 the extreme angle, the amplifier gain should adjust to 3 may determine the 3dB frequency from the type for to.Three steps fil

46、ter performance has the improvement. They have same 3, but K 0value respectively different, always gain then for type (2313) and type (2314)product, namelyOnce extracted in 217, three extremes amplifiers obtained do not have the peak to get up the smoothest response condition were three extremes mol

47、ds are equal, and inowhich contained a pair of angle is the 60 conjugate complex numbers.To the abovechoice, (2315) may determine from the type, type (2316) center K =2. 2241 Direct-current power supplyFor the electronic equipment use power source in the entire equipment cost, the size, the weight,

48、as well as in the design ingenuity holds the very great proportion the situation is a common occurrence.When inputs for the alternating voltage, the direct-current power supply has three basic parts generally. These three parts show in chart in 24 1 block diagram.The rectifier will input the exchang

49、e to become belt direct current and to exchange two kind of components pulsation profiles. In certain application situations, likes the galvanization and the battery charge, this kind of output may be suitable. But the majority application allc.requests to filter out the a. c. component. The filter

50、circuit output to the audio amplifier and many radio receivers is possibly the appropriate power source. But, must cause the numeral and simulate these two kind of integrated circuit normal work, the supply voltage is stable is very important frequently. This main elaboration rectification and filte

51、r process. The voltage steady rule is this flees other parts of subjects.Rectifier Filter Exchange inputvoltage-stabi1izerDirect-current outputchart 241 power source three basic partsRectificationBecause 242 show for the single-way rectifier electric circuit, is composed by the diode and the load resistance series. The power frequency input voltage sends outthe unidirectional current through the diode, latter produces the pulsating voltage in the load beginnings and ends. The load voltage has the non-vanishing mean value V. d cTherefore, the rectifier will input the