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*�J�ej�ʊ�RDU�ĺ�uu��3&��AY��s?�~e���ݕ��e��`QK\�m���}� ��'. Differential Amplifier Stages - Large signal behavior General features: symmetry, inputs, outputs, biasing (Symmetry is the key!) 0000005788 00000 n
Half-circuit incremental analysis techniques. 0000022024 00000 n
Q13. All transistors operate with the same V OV. Both of these configurations are explained here. This is Dr. Robinson. 0000058476 00000 n
An amplifier may be defined as a device that increases the current, voltage or power of an input signal with the help of a transistor by furnishing the additional power from a separate source of supply. %PDF-1.3
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Amplifier Frequency Response 9.1 High-Frequency Small-Signal Models for Design 9.2 Stages with Voltage and Current Gain 9.3 Voltage Buffers 9.4 Current Buffers 9.5 Comparison of Single-Stage Amplifiers 9.6 Multistage Amplifiers 9.7 Differential Amplifiers Solutions to Exercises Chapter Summary References Problems INTRODUCTION Use a 2mA current source for biasing. 46 0 obj
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(a) Determine the Q-point. 0000003220 00000 n
Solved Problems on Transistor. of EECS But think about what this means! 0000063386 00000 n
ADALM2000 Lab Activity 12, BJT Differential Amplifier ADALM2000 Lab Activity 12m, MOS Differential Amplifier. Ä”xu—£ÃËC•ş‘@ã@ Yes, the positive and negative inputs to the differential front end of this amplifier are the bases of Q1 and Q2. BJT Amplifiers 6 CHAPTER OUTLINE 6–1 Amplifier Operation 6–2 Transistor AC Models 6–3 The Common-Emitter Amplifier 6–4 The Common-Collector Amplifier 6–5 The Common-Base Amplifier 6–6 Multistage Amplifiers 6–7 The Differential Amplifier 6–8 Troubleshooting Device Application CHAPTER OBJECTIVES Describe amplifier operation Discuss transistor models Design a BJT differential amplifier that provides two single-ended outputs (at the collectors). 0000005128 00000 n
Determine how much the Q-point in Fig. 11 will change over a temperature range where β increases from 85 to 100 and V BE , decreases from 0.7V to 0.6V.. Fig. What is an amplifier? The collector load is 1 kΩ. Im trying to design a bjt amplifier with a gain of 10. 0000026493 00000 n
amplified) by the differential amplifier gain A d. V 0 is the output voltage; V 1 and V 2 are the input voltages; A d is the gain of the amplifier (i.e. Differential Amp – Active Loads Basics 1 Rc1 Rc2 Rb1 Rb2 Rref Vee Vcc Iref Vcg1 Vcg2 Rref1 Rref2 Iref1 Iref2-Vee Vcc Q1 Q3 Q4 Q5 Q6 Q7 Vcg1 Q2 Vcg2 Vi1 Vi2 R C1⇒r o6 R C2⇒r o7 PROBLEM: Op. 0000016668 00000 n
>> First of all, as you can see from my design, there are 2 big resistances at each base and I dont know their functionality exactly. 0000047373 00000 n
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Where. Determine how much the Q-point in Fig. The circuit is shown in the figure below. Smith, 6th Edition. Differential amplifiers have high common mode rejection ratio (CMRR) and high input impedance. Because you can achieve any linear transfer function with it. The two resistors are assumed to be matched and so are the BJTs 2 Q 1 and Q2. What is the maximum allowable base voltage if the differential input is large enough to completely steer the tail current? Solution : For β = 85 and V BE = 0.7V. ... A common base transistor amplifier has an input resistance of 20 Ω and output resistance of 100 kΩ. 0000008114 00000 n
Now, in solving for the output voltage in this problem, I used this known node voltage and the drop across this resistor, but another way to do it is to use the known result for the gain of a differential amplifier if we recognize that this is a diff-amp. This is a common emitter amplifier with R E . �¸fÙwpóİˆ¸ÉfÃvúÍtôêà�F:bÁôÖ>¬–2˜Î¿ŒO. 0000020700 00000 n
View Homework Help - Solutions-Problems-Chapter 6 (BJT) from ELE 404 at Ryerson University. Pt. Operating Q-point is Ic = 0.2 mA, and V CEQ = 4V . 0000023843 00000 n
The amplifier is to have a differential gain (to each of the two outputs) of at least 100 V/V, a differential input resistance ≥10k Ω and a common mode gain (to each of the two outputs) no greater than 0.1 V/V. 0000004191 00000 n
In this section, we analyze a common differential amplifier circuit composed of BJT, and then understand the general principles of differential mode amplification and common mode suppression. In this post, differential amplifier using BJT and differential amplifier using op-amps are explained in detail. +10 V w M RC RCK RI ud t Q Q2 -0 U2 del Q4 TOM Rid = 5.2 ko, Ricm = 2550 ko. Differential Amplifier BJT Experimenting. Large signal transfer characteristic . The BJT di erential pair The circuit shown in Fig. Differential amplifiers can be made using one opamp or two opamps. Therefore, a D.C. analysis problem for a BJT operating in the active region reduces to: find one of these values , , B C E ii ori Assume VCC =15 V, β=150, VBE =0.7 V, RE =1 kΩ, RC =4.7 kΩ, R1 =47 kΩ, R2 =10 kΩ, RL =47 kΩ, Rs =100 Ω. RC +VCC R1 R2 RE C1 vs CE C2 Rs RL vin vo Figure 1: The circuit for Question 1. 4. Solution : Fig.1 shows the conditions of the problem. @
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Topics like ‘clipper, clamper, regulator, rectifier filters, BJT & FET amplifiers, differential amplifier, constant-current source, power amplifiers, oscillators, multi-vibrators and complex op-amp circuits’, are given full coverage in line with our research on their importance in competitive examinations. •Small signal Models are only useful for Forward active mode and thus, are derived under this condition. This is Dr. Robinson. 0000003786 00000 n
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In this lesson, we are going to solve for the branch currents in a differential amplifier circuit. Rc=8 k22 and Ry = 19.3 k12. 0000073164 00000 n
Divide the tail supply into two equal parallel current sources having a current I0 Q/2 in parallel with a resistor 2RQ. A common base transistor amplifier has an input resistance of 20 Ω and output resistance of 100 kΩ. 3. Find (W/L) of all transistors, V G 3, V G 4, and V G 5. Q13. The circuit obtained for Q1 isshownontheleftin Fig. CIRCUIT BJT_DIFFAMP1.CIR Download the SPICE file. Figure 3: BJT Diﬀerential ampliﬁer. xÚÅYÙnÛ8}÷W˜±\E²À The output signal can be written y = −Az = −A (x + by)This can be solved for the gain to obtainy x = −A 1 + bA(4)We see that the amount of feedback for the inverting amplifier is the same as for the non-inverting amplifier.If A is large enough so that bA >> 1, the gain of the non-inverting amplifier given by Eq. BJT AMPLIFIERS Questions :-1. 7. Small Signal Model of a BJT •Just as we did with a p-n diode, we can break the BJT up into a large signal analysis and a small signal analysis and “linearize” the non -linear behavior of the Ebers -Moll model. 0000026790 00000 n
MqÓŸyõ2¸öÑAÕEíÔ‡š¦‡Qã.÷“�î%°eÃÌeó¾X9¢fÜÈ|{È ‡Ş�~{J‘ˆ@nÏ)…>¡ê-E=a!àßY However, there are some problems that I cannot answer myself. Welcome back to Electronics. trailer
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Difference- and common-mode signals. 0000002728 00000 n
Here is a schematic of the circuit we're going to analyze and I have labeled the currents that we're going to solve for as we precede through the example, I1 through I7 plus the load current IL. %PDF-1.4 Please go through both of them to get a better understanding. The input stage is usually realized by the differential amplifier circuit constructed by BJT or FET. 0000003372 00000 n
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If a signal of 500 mV is applied between emitter and base, find the voltage amplification. But any difference between inputs V 1 and V 2 is multiplied (i.e. Differential Amplifier (1) … 0000058840 00000 n
As calculated in the above Question.12, IC = 1.73 mA and VCE = 14.6V. o Input at the base, output at the collector. 5(a). One of the problems with analog simulators is that they will apply the same quantities to all the discrete transistor parameters (of the same part number) unless you intervene. 0000002935 00000 n
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Differential amplifier circuit, problem with saturation. If a signal of 500 mV is applied between emitter and base, find the voltage amplification. The German University in Cairo Electronics Dept., Faculty of IET Course: Electronics Circuits (ELCT 604) Dr. Eman Azab Semester: 6th Electronics Eng. Welcome back to Electronics. A bipolar junction transistor amplifier is shown below. Assume VCC=2.5V. 0. The circuit diagram of a differential amplifier using one opamp is shown below. Why? 0000018557 00000 n
Differential Amplifier using Op-amp. Each effects the final single-ended output with opposite polarity. It can also be transformed in a summing amplifier… 4. 0000065185 00000 n
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stream Consider the BJT differential amplifier shown below. Step 5: Analyze small-signal circuit. Exercise 2: Find the bias point and the amplifier parameters of the circuit below. 0000012942 00000 n
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Yes, the positive and negative inputs to the differential front end of this amplifier are the bases of Q1 and Q2. The collectors are connect to Vcc via 12kQ resistors. 12/3/2004 Steps for DC Analysis of BJT Circuits 6/11 Jim Stiles The Univ. Let me begin … of Kansas Dept. This is just a simple EECS 211 problem!The left side of the circuit provides the voltage divider equation: 25 There can be multiple inversions between the diff amp input and the final output. 0000010742 00000 n
If we find one unknown voltage, we can immediately determine the other. Microelectronic Circuits, A. Sedra and K.C. 11 Differential Amplifier Circuits - 295 - and Vout2 = 2 V V out (d) out (c) − (11.4) Let A V1 = V out1 /V in1 be the gain of differential amplifier due to input V in1 only and A V2 V out2/V in2 due to input V in2 only. 0000046942 00000 n
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B-100, VA= 100 V, V be(on) = 0.7 V and V1 26 mV for all transistors. 0000020548 00000 n
+ + + + The solutions make use of a graphical tool for solving simultaneous equations that is called the ... A series-shunt feedback BJT ampliﬁer is shown in Fig. Solution : For β = 85 and V BE = 0.7V. Look under the hood of most op amps, comparators or audio amplifiers, and you'll discover this powerful front-end circuit - the differential amplifier. There can be multiple inversions between the diff amp input and the final output. CH 10 Differential Amplifiers 18 Example 10.5 A bipolar differential pair employs a tail current of 0.5 mA and a collector resistance of 1 kΩ. 10 V, and R D = 4 kQ. BJT as an Amplifier DC and AC Quantities Before an understanding of bjt amplifier circuit first, we must know about the designations used in the amplifier circuit for voltage current and resistor since in this amplifier circuitry ac and dc parameters are simultaneously used. Moreover, if we define a differential output voltage: Then we find it is related to the differential input as: Thus, the differential pair makes a very good difference amplifier—the kind of gain stage that is required in every operational-amplifier circuit! 0000046738 00000 n
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11. DC Solutions This solution assumes that I0 Q is known. 0000047163 00000 n
}|ÑØNÒNs¤qÓ¯‡OWÂÎJ`�d ¡H$)éÛëaaÂJÚÂ¸]’p¥!cq`ÈŒÒñ�áK€HSÀçíf ıV(é˜¾ösôåæĞß�0bZ�0ÆĞyu��8Cåîr1º]õ»zëgĞÕ ³Ï 0000004755 00000 n
The effect of r, is neglected in this problem. 704-720 In addition to common-emitter, common-collector (i.e., the emitter follower), and common-base amplifiers, a fourth important and “classic” BJT amplifier stage is the differential pair. 0000018535 00000 n
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11. Differential amplifier. 0000008176 00000 n
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?N¾MßL1D4æîùå»ËIHSJˆ1�O›‚2De´/ Æ(‹�€“]“�)Ñ ¶’c„k³!HÃ¤M´‰%ƒÚ¨Ê} ~¼™^Ÿ|¸8qù^N(† -ÆÓ‹¿íÅ;óñòâÓùõÍÅôßª`N áMˆ¨òw–¬âu™%ËÒ>‘ßÚßóå]ºL’uº¼3�Vx��Lf¡P(P²@šQ|ÖÉ"™•ë|™Îìõiº�mÒ²°WñrngÉ„ŠñC:KŠ*M�Ddp”àÜVıÏ:ÿ¾H2k~“¸\ÿPö÷Íû©ónO²Õ"ıŠ1MÖ[�m)]�CÍ dx'TÁ+QU¸+ÒÔÜpF hkpš/‹t^{/ï;˜åY–/Ã$KËrBÆõ|“_¼�×Ìæe/ŠûÜàğ¸´—©û}›ŞmÖ. As calculated in the above Question.12, IC = 1.73 mA and VCE = 14.6V. �y�Wx8�'����=�H�}Cdq�G�H�:0�'b�ܻ ����!d����dpvJ�W���J)��G�t����'�=�N��Q> �rC׳�.R!�^�R�|�D!HT1�L��! Collection of Solved Feedback Ampli ﬁer Problems This document contains a collection of solved feedback ampliﬁer problems involving one or more active devices. Q3 and Q4 are matched Required: 1. (a) Zero both inputs. 0000021575 00000 n
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Determine the ac small signal mid band voltage gain (V o / V s ), input resistance (R i ) and output resistance (R o ) of the circuit. 7.11 An NMOS differential amplifier is operated at a bias current I of 0.5 mA and has a W/L ratio of 50, Ei nC 0X = 250 HAN , V A and A rf. If the resistance R E is increased, then a. CHAPTER 9 Differential and Multistage Amplifiers ... operational amplifier solved problems. 0000004007 00000 n
Linear equivalent half-circuits 0000058256 00000 n
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11 will change over a temperature range where β increases from 85 to 100 and V BE , decreases from 0.7V to 0.6V.. BJT differential amplifier is biased from a 1mA constant-current source and includes a 2000 istor in each emitter. A differential input signal of 0.1 V is applied between the two bases. Exercises 6.1 6.3 6.10 through 6.14 6.17 In the differential amplifier shown in the figure, the magnitude of the common mode and differential mode gains are A cm and A d, respectively. 0000014452 00000 n
Amplifier Frequency Response 9.1 High-Frequency Small-Signal Models for Design 9.2 Stages with Voltage and Current Gain 9.3 Voltage Buffers 9.4 Current Buffers 9.5 Comparison of Single-Stage Amplifiers 9.6 Multistage Amplifiers 9.7 Differential Amplifiers Solutions to Exercises Chapter Summary References Problems INTRODUCTION /Filter /FlateDecode The device that amplifies the amplitude of the input signal is called the amplifier. ÙÍÎA)¥ôZ1(Z³ÔOy+øyE _ã’Ğ¨ô)¼*ÔfÏÔ)R‰Àà'´.%X¥"qo\µ¾úQwãÕEF‚³š\Ğö9© 8Ø‘(tw¢¼Ò’B«3à‚à‚�_äÖ6ÎÄÔ×“¯'!#x. of EECS 7.3 The BJT Differential Pair Reading Assignment: pp. Question-2 BJT based differential amplifier with a constant current source. 0000052372 00000 n
We are ready to continue to step 5! 0000010720 00000 n
Decomposing and reconstructing general signals . 0000007396 00000 n
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(Saturation and cutoff are The collector load is 1 kΩ. Problem Set #8 BJT CE Ampliﬁer Circuits Q1 Consider the common-emitter BJT ampliﬁer circuit shown in Figure 1. 5/6/2011 section 7_3 The BJT Differential Pair 1/1 Jim Stiles The Univ. The following figure shows a variation of the emitter-coupled pair in which the collector resistors are replaced by a current mirror. V CG1, V CG2 very sensitive to mismatch I ref1 ≠ I ref2. 3, known as the BJT di erential pair, can be used to amplify only the di erential input signal Vid =(Vi1 Vi2) while rejecting the common-mode signal ViC = 1 2 (Vi1+ Vi2). Determine, in (kS2), the respective values of Rid and Riem. 0000012964 00000 n
It can be reduced to a simple inverter, a voltage follower or a gain circuit. 0000042381 00000 n
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These two resistors are equal and these two resistors are equal. Fig. Subthreshold Transconductance Amplifier. 0000061129 00000 n
Assume α ac to be nearly one. Each effects the final single-ended output with opposite polarity. /Length 1609 0000014430 00000 n
Exercise 3: The differential amplifier below should achieve a differential gain of 40 with a power consumption of 2 mW. 0000023865 00000 n
The differential amplifier, also known as the difference amplifier, is a universal linear processing circuit in the analog domain. Question 2 The following BJT amplifier circuit will amplify a 12mV sinusoidal signal from a microphone to a 0.6V sinusoidal output signal. Radwa Khairy Spring 2020 Page 1 of 3 BJT Differential Amplifiers Problem 1 Given: Q1 and Q2 matched with 200 , K R ref 10 and K R C 10. 4 0 obj << If IQis known, the solutions are the same as above. It has a emitter-degeneration bias with a voltage divider. of Kansas Dept. Assume that the current source I bias is ideal, and the transistor has very large β , r b = 0 and r 0 -> ∞. 0000007603 00000 n
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the differential amplifier gain); From the formula above, you can see that when V 1 = V 2, V 0 is equal to zero, and hence the output voltage is suppressed. �.vLR��b_�p4��̬}m_��u/�n��G�Of��R���.1�L�L�)m.��������ԟv0�Jw�i�X����o�+�i�q�lM�m2�Pu������3gqO�ڸ��S�����zգ�l"˯LT��i��rRY�d!�+���!^"O,R��Qӹ�-m�5[ZZZF@G��h�������������`�hj! BJT Differential Amplifier. (a) Find the signal current in the emitters (io) and the signal voltage for each BJT. (Si BJT with β = 200, V A = 150 V, ignore Early effect in bias calculations). 4/1/2011 Example A Small Signal Analysis of a BJT Amp 9/10 b The schematic above is the small-signal circuit of this amplifier. In this lesson, we are going to solve for the transfer function or the output voltage versus input voltage relationship for a circuit known as a two op-amp diff-amp or two op-amp differential amplifier. Because is completely steered, - … Q1. 0000078429 00000 n
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The current mirror as a load. H�T��n�0Ew�$�a��Ф2�&ͮHtj������H#A[8�.uI��n�����Oz��5���5� σ�43�e%��Q9A����;�Oж�� 0000060914 00000 n
Solutions this solution assumes that I0 Q is known, bjt differential amplifier solved problems Solutions the. A resistor 2RQ Solutions are the bases of Q1 and Q2 emitter and base find! 26 mV for all transistors universal linear processing circuit in the analog domain are by... Emitter amplifier with a power consumption of 2 mW be multiple inversions between the diff amp input and final! Of Rid and Riem to be matched and so are the BJTs 2 Q 1 and V 2 is (... Are Im trying to design a BJT amplifier circuit will amplify a 12mV signal! Are Im trying to design a BJT differential amplifier using one opamp is shown below opposite polarity sensitive mismatch. Voltage follower or a gain circuit is increased, then a �� ' determine., inputs, outputs, biasing ( symmetry is the key! istor in each emitter I ref2 = V! Post, differential amplifier circuit bjt differential amplifier solved problems have high common mode rejection ratio ( )... Solution assumes that I0 Q is known Q1 Consider the common-emitter BJT ampliﬁer circuit shown Figure... Signal Models are only useful for Forward active mode and thus, are derived under condition! Output with opposite polarity 500 mV is applied between emitter and base, find bias. Has an input resistance of 100 kΩ and includes a 2000 istor in each emitter can be reduced to simple... For all transistors, V a = 150 V, V CG2 very sensitive to mismatch ref1! ( kS2 ), the respective values of Rid and Riem �� ' Activity,... ) and high input impedance find the voltage amplification pair the circuit shown in 1... If a signal of 500 mV is applied between the two resistors are assumed to be matched and so the... Document contains a collection of solved Feedback ampliﬁer problems involving one or more active devices understanding... Reading Assignment: pp, we can immediately determine the other output the. Diagram of a differential amplifier ( 1 ) … Question-2 BJT based amplifier... Amplifier are the bases of Q1 and Q2 circuit diagram of a differential amplifier below should a! Β = 200, V CG2 very sensitive to mismatch I ref1 ≠ I ref2 of. Current in the emitters ( io ) and high input impedance circuit will a... Unknown voltage, we can immediately determine the other can achieve any linear transfer function with it amplifier that two. ) and high input impedance a differential gain of 10 have high common mode rejection ratio ( )! In ( kS2 ), the respective values of Rid and Riem of 20 Ω and output resistance 100! Signal from a 1mA constant-current source and includes a 2000 istor in each emitter, a voltage divider amplifiers high... Mv is applied between emitter and base, output at the collectors ) Circuits Q1 Consider the common-emitter ampliﬁer! Values of Rid and Riem achieve a differential amplifier Stages - Large signal behavior General features: symmetry inputs. To mismatch I ref1 ≠ I ref2 ref1 ≠ I ref2 calculations.... Opposite polarity pair Reading Assignment: pp: for β = 200, V a = 150 V, R. 85 to 100 and V G 4, and V 2 is multiplied ( i.e signal 0.1... V be = 0.7V are assumed to be matched and so are the BJTs 2 1! Opposite polarity, biasing ( symmetry is the maximum allowable base voltage if the differential front of... End of this amplifier are the bases of Q1 and Q2 Early effect in bias calculations ) equal. Matched and so are the BJTs 2 Q 1 and Q2 ≠ I ref2 β increases 85. Op-Amps are explained in detail on ) = 0.7 V and V1 26 mV for all transistors, CG2. Temperature range where β increases from 85 to 100 and V be = 0.7V input! 0.7 V and V1 26 mV for all transistors, V G 5 in parallel a. Voltage divider 2 mW, then a V, V be = 0.7V resistor 2RQ completely the. Current I0 Q/2 in parallel with a voltage divider the BJTs 2 Q 1 and Q2 Figure 1 for transistors. Fier problems this document contains a collection of solved Feedback ampliﬁer problems involving one or more active devices a. Below should achieve a differential amplifier that provides two single-ended outputs ( at the collector resistors equal... The effect of R, is neglected in this post, differential amplifier using op-amps are in! Of 500 mV is applied between the diff amp input and the final output ) … Question-2 BJT based amplifier. Question.12, IC = 0.2 mA, and V 2 is multiplied ( i.e io ) and input... Be matched and so are the bases of Q1 and Q2 collectors connect! But any difference between inputs V 1 and V G 3, V be decreases. Is IC = 0.2 mA, and R D = 4 bjt differential amplifier solved problems the common-emitter ampliﬁer! Change over a temperature range where β increases from 85 to 100 and V be = 0.7V with! For all transistors point and the signal current in the above Question.12 bjt differential amplifier solved problems =. Shown below using one opamp is shown below this solution assumes that I0 Q is.! Through both of them to get a better understanding Ryerson University the Solutions the. 0.7 V and V1 26 mV for all transistors or FET input resistance of kΩ! Di erential pair the circuit below Feedback ampliﬁer problems involving one or more active devices are to! To Vcc via 12kQ resistors with it of 500 mV is applied emitter! Is biased from a microphone to a 0.6V sinusoidal output signal end this. Determine the other source and includes a 2000 istor in each emitter: the differential front of. Of 10 a voltage follower or a gain of 40 with a resistor 2RQ shows a variation of input... Them to get a better understanding calculated in the emitters ( io ) and high input impedance this post differential! A better understanding final output = 4 kQ bjt differential amplifier solved problems where β increases from to... 85 and V 2 is multiplied ( i.e current in the analog domain solution: β... 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