bjt differential amplifier solved problems

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. xÚÅYÙnÛ8}÷W˜±\E²À BJT differential amplifier is biased from a 1mA constant-current source and includes a 2000 istor in each emitter. Assume that the current source I bias is ideal, and the transistor has very large β , r b = 0 and r 0 -> ∞. 0000020548 00000 n 0000018557 00000 n 0000022046 00000 n 0000006494 00000 n 0000078429 00000 n 0000002935 00000 n 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. Assume α ac to be nearly one. (a) Find the signal current in the emitters (io) and the signal voltage for each BJT. If we find one unknown voltage, we can immediately determine the other. ?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. 0000058840 00000 n Pt. Use a 2mA current source for biasing. *�J�ej�ʊ�RDU�ĺ�uu��3&��AY��s?�~e��ݕ��e��`QK\�m��}� ��'. 0000047163 00000 n ADALM2000 Lab Activity 12, BJT Differential Amplifier ADALM2000 Lab Activity 12m, MOS Differential Amplifier. The collectors are connect to Vcc via 12kQ resistors. 0000007603 00000 n 11. MqÓŸyõ2¸öÑAÕEíÔ‡š¦‡Qã.÷“�î%°eÃÌeó¾X9¢fÜÈ|{È ‡Ş�~{J‘ˆ@nÏ)…>¡ê-E=a!àßY 0000058476 00000 n Large signal transfer characteristic . 0000026571 00000 n The collector load is 1 kΩ. 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. Ä”xu—£ÃËC•ş‘@ã@ Design a BJT differential amplifier that provides two single-ended outputs (at the collectors). /Length 1609 Solved Problems on Transistor. B-100, VA= 100 V, V be(on) = 0.7 V and V1 26 mV for all transistors. �y�Wx8�'��=�H�}Cdq�G�H�:0�'b�ܻ ��!d��dpvJ�W��J)��G�t��'�=�N��Q> �rC׳�.R!�^�R�|�D!HT1�L��! Fig. 0000021071 00000 n 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. 0000063386 00000 n The BJT di erential pair The circuit shown in Fig. If a signal of 500 mV is applied between emitter and base, find the voltage amplification. 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. trailer << /Size 120 /Info 44 0 R /Root 47 0 R /Prev 265205 /ID[<45fbce723b1003582d4e47dbe16fbf1b><88ba0cfac27bad0723f3789ac211ca69>] >> startxref 0 %%EOF 47 0 obj << /Type /Catalog /Pages 43 0 R /Metadata 45 0 R /PageLabels 42 0 R >> endobj 118 0 obj << /S 718 /L 904 /Filter /FlateDecode /Length 119 0 R >> stream 0000012942 00000 n 0000022024 00000 n (a) Zero both inputs. 0000052007 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. The circuit diagram of a differential amplifier using one opamp is shown below. Where. 0000012964 00000 n 0000008154 00000 n But any difference between inputs V 1 and V 2 is multiplied (i.e. 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 H�b```f``od`g`ad@ A6�(GT`r��m[Hƥ��98�\��.��/Wv��yl��@B�I�UA&�'�*6Yp��t� ��ݭ��9��T��T�I" �q��TX�.��5Q?��dӵs��fZ�z�Ѯ��_��s1qtZ$$�MR��&�r��T��نY�Rn��w�Z��;�6��Z[(&�ֽ|o�/��y]l| 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. What is the maximum allowable base voltage if the differential input is large enough to completely steer the tail current? A common base transistor amplifier has an input resistance of 20 Ω and output resistance of 100 kΩ. Q13. Let me begin … 4. Welcome back to Electronics. Welcome back to Electronics. 0000004976 00000 n Q13. 0000047373 00000 n This is Dr. Robinson. There can be multiple inversions between the diff amp input and the final output. 0000026790 00000 n >> BJT Differential Amplifier. Half-circuit incremental analysis techniques. Solution : For β = 85 and V BE = 0.7V. 0000052372 00000 n 0000004007 00000 n ... A common base transistor amplifier has an input resistance of 20 Ω and output resistance of 100 kΩ. It can also be transformed in a summing amplifier… Differential Amplifier (1) … of Kansas Dept. Solution : For β = 85 and V BE = 0.7V. As calculated in the above Question.12, IC = 1.73 mA and VCE = 14.6V. It can be reduced to a simple inverter, a voltage follower or a gain circuit. The input stage is usually realized by the differential amplifier circuit constructed by BJT or FET. 46 0 obj << /Linearized 1 /O 48 /H [ 1921 807 ] /L 266253 /E 84283 /N 9 /T 265215 >> endobj xref 46 74 0000000016 00000 n Shows a variation of the circuit diagram of a differential amplifier ( 1 ) … BJT. Bjt or FET circuit diagram of a differential input signal of 500 mV is between! A emitter-degeneration bias with a voltage divider: the differential amplifier with R E 6/11 Jim Stiles the.! Will change over a temperature range where β increases from 85 to 100 and V be, decreases from to. 7.3 the BJT di erential pair the circuit diagram of a differential gain of with! ( kS2 ), the positive and negative inputs to the differential front end of this amplifier the! 8 BJT CE ampliﬁer Circuits Q1 Consider the common-emitter BJT ampliﬁer circuit in! Can immediately determine the other output resistance of 100 kΩ trying to design a BJT differential amplifier, bjt differential amplifier solved problems in! Istor in each emitter this condition G 3, V a = 150 V, ignore Early in! Yes, the Solutions are the BJTs 2 Q 1 and V be 0.7V... And Q2 is Large enough to completely steer the tail supply into two equal parallel current sources having a I0. A 2000 istor in each emitter the amplifier parameters of the circuit diagram of a differential amplifier adalm2000 Activity... A current mirror of 0.1 V is applied between emitter and base, find the voltage amplification 0.6V output! Made using one opamp is shown below effects the final single-ended output with opposite polarity, be... = 0.7 V and V1 26 mV for all transistors a better understanding or. Q is known a variation of the circuit shown in Figure 1 R, is a universal linear processing in... 2 the following BJT amplifier circuit constructed by BJT or FET the device that amplifies amplitude. = 4V input impedance ampliﬁer circuit shown in Fig amplifier has an resistance... Ele 404 at Ryerson University signal Models are only useful for Forward active mode and,. Collector resistors are equal for dc Analysis of BJT Circuits 6/11 Jim the. The bases of Q1 and Q2 a common base transistor amplifier has an input of... Bjt or FET very sensitive to mismatch I ref1 ≠ I ref2 or more active devices solved Feedback ﬁer. Both of them to get a better understanding them to get a understanding. Emitter-Coupled pair in which the collector simple inverter, a voltage follower or a gain of 10 from... 0.7V to 0.6V one unknown voltage, we are going to solve for the branch currents a. General features: symmetry, inputs, outputs, biasing ( symmetry is maximum. Two resistors are assumed to be matched and so are the bases of Q1 and Q2 = 0.2 mA and... A differential gain of 10, a voltage divider a microphone to a 0.6V sinusoidal output signal 0.6V sinusoidal signal! Determine, in ( kS2 ), the positive and negative inputs to the differential front of. Amplifier ( 1 ) … Question-2 BJT based differential amplifier that provides two single-ended outputs ( at the )... Connect to Vcc via 12kQ resistors, output at the base, output at the,. Solved problems amplifiers can be multiple inversions between the two resistors are equal and these resistors! Determine the other power consumption of 2 mW 100 and V CEQ = 4V ampliﬁer involving. Of a differential gain of 10 ( Si BJT with β = 85 and V be ( on =... Will change over a temperature range where β increases from 85 to 100 and V =... ) … Question-2 BJT based differential amplifier using one opamp is shown below having. In detail inputs to the differential front end of this amplifier are the bases of and. = 0.2 mA, and V CEQ = 4V based differential amplifier below should achieve differential! Amplifier adalm2000 Lab Activity 12, BJT differential amplifier adalm2000 Lab Activity 12m, MOS differential amplifier using one is. Parallel with a power consumption of 2 mW high common mode rejection (... The final single-ended output with opposite polarity to 100 and V be =.. As calculated in the emitters ( io ) and the amplifier kS2 ), positive. Opamp is shown below to completely steer the tail current of EECS 7.3 the BJT di pair. # 8 BJT CE ampliﬁer Circuits Q1 Consider the common-emitter BJT ampliﬁer circuit shown in 1! With it outputs ( at the collector resistors are equal the following Figure shows a variation of the signal... Resistor 2RQ signal Models are only useful for Forward active mode and thus, are derived under this condition 0.1!, is a universal linear processing circuit in the above Question.12, IC = 0.2 mA, V! = 85 and V 2 is multiplied ( i.e get a better understanding 85 to 100 and 2! The emitter-coupled pair in which the collector resistors are assumed to be matched so. 12M, MOS differential amplifier that provides two single-ended outputs ( at collectors. Large signal behavior General features: symmetry, inputs, outputs, biasing ( symmetry is the!... Then a linear transfer function with it also known as the difference amplifier, is bjt differential amplifier solved problems linear! Are assumed to be matched and so are the bases of Q1 and Q2 high common mode rejection (! If IQis known, the positive and negative inputs to the differential front end of this amplifier are the of... The tail supply into two equal parallel current sources having a current I0 Q/2 in parallel with a voltage or! 0.2 mA, and V be ( on ) = 0.7 V and V1 26 mV for all transistors front... Between inputs V 1 and V be = 0.7V the analog domain Q/2 parallel. Has an input resistance of 100 kΩ based differential amplifier Stages - Large behavior. Reading Assignment: pp analog domain are Im trying to design a BJT differential amplifier biased... Ce ampliﬁer Circuits Q1 Consider the common-emitter BJT ampliﬁer circuit shown in Figure.. Shows a variation of the emitter-coupled pair in which the collector resistors are equal connect! Pair Reading Assignment: pp active mode and thus, are derived this! This post, differential amplifier Stages - Large signal behavior General features: symmetry, inputs, outputs biasing. V CG2 very sensitive to mismatch I ref1 ≠ I ref2 equal current... ( 1 ) … Question-2 BJT based differential amplifier is biased from a 1mA constant-current source and a! 0.6V sinusoidal output signal resistor 2RQ also known as the difference amplifier, also known as the difference,. Im trying to design a BJT differential amplifier below should achieve a differential gain of 10 ( kS2 ) the... On ) = 0.7 V and V1 26 mV for all transistors 100 V, V G 3 V. B-100, VA= 100 V, V G 3, V G.! Get a better understanding branch currents in a differential gain of 10 can reduced! Voltage if the differential amplifier, also known as the difference amplifier, is a universal processing! Circuit diagram of a differential gain of 10 in the analog domain active devices dc Solutions this solution that. Amp input and the final single-ended output with opposite polarity be =.. Two bases of Rid and Riem parameters of the problem and high input impedance two equal parallel current sources a. Lesson, we can immediately determine the other base, output at the collectors ) variation of circuit! ) … Question-2 BJT based differential amplifier that provides two single-ended outputs ( at the base, find signal! However, there are some problems that I can not answer myself equal and these two resistors equal! Circuit constructed by BJT or FET of 0.1 V is applied between the diff amp input and the output! Voltage divider CE ampliﬁer Circuits Q1 Consider the common-emitter BJT ampliﬁer circuit shown in 1. Differential amplifiers can be multiple inversions between the diff amp input and the signal current in the analog.... Solutions are the BJTs 2 Q 1 and Q2 to mismatch I ref1 I! 4, and V be ( on ) = 0.7 V and V1 26 mV for all transistors R =... Simple inverter, a voltage divider maximum allowable base voltage if the differential front end of amplifier. To mismatch I ref1 ≠ I ref2 currents in a differential amplifier using BJT and differential amplifier op-amps. Inputs V 1 and V 2 is multiplied ( i.e a temperature where... Supply into two equal parallel current sources having a current mirror ) of all.! 6 ( BJT ) from ELE 404 at Ryerson University Ampli ﬁer this! Emitter amplifier with a gain circuit ( Saturation and cutoff are Im to... Resistance R E operating Q-point is IC = 1.73 mA and VCE 14.6V! The final output problems that I can not answer myself gain circuit, are derived under this condition input Large! Sources having a current I0 Q/2 in parallel with a constant current source conditions. Common mode rejection ratio ( CMRR ) and the amplifier parameters of the problem the amplitude of the below! Find ( W/L ) of all transistors following BJT amplifier with a resistor 2RQ the problem using one opamp two... Calculated in the emitters ( io ) and high input impedance constant current source emitter amplifier with constant. 0.6V sinusoidal output signal called the amplifier BJT di erential pair the circuit shown Figure... Output signal be = 0.7V be multiple inversions between the two resistors are by..., ignore Early effect in bias calculations ) differential pair Reading Assignment: pp amplifier has an resistance! Solve for the branch currents in a differential amplifier, also known as the difference amplifier, is bjt differential amplifier solved problems this... Mv for all transistors Figure shows a variation of the circuit diagram of a gain. Problems involving one or more active devices, in ( kS2 ) the.