Question

1) For the bridge opamp circuit in the figure, find the total voltage gain expression Vo/Vin when the opamps are not saturated. (20p) When Vin (4th) (2001Tt) signal is applied to the input and R1 = R4 = 10K, R2 = R3 = 20K resistance values are selected, draw a single period of the Vo output signal by specifying its time and amplitude values. R2 +12V R1 Vin 1-12V RL Vo +12V -12V WW R3 R4

Answer 1

Here , both opamp is negative feedback so we can apply virtual ground concept by which voltage at the inverting terminal becomes equal to the voltage at the non inverting terminal.

For calculating Vo we have to calculate the output of each opamp seperately.

R2 Vio Ri (V-) Not + (V+) here, Inverting terminal Voltage Vo Hage at Non terminal terminal V by Virtual Ground Concept, (V) (V+) Also, vt = 0 { Ground? so, V. Io volt Apply KCL at (V) node, Vin (V.) (-) - Vol Ri R2 Vin Not = Ri Rz Rr Vin Vos R 1

(V+) Voz Vin t. (V)9 by Voltage divider drule, - Voz ( Ru) Rut R₃) R3 (V.) R And - Vin by Virtual Ground Concept, (V+ = V.) so, Ry Von Center Ru + R3 Voz + R3 Vign Therefore solta ge across Resistance R will be given, Von Vol Vo il Rz R Vin R3 Vin 1 Ru Vo + R3 Ru :) Vin R For R, 1) Ry 10k and R2 = R3 - 20k Vo - – 5 Vin (1 + 2 + 2) Vin - 5 Vin V. D

- Vin 4 sin ( 200 Tt) For Nout - 20 sin (200 tt) Vin Vin 4 /1 ZIT wt 20 Vout 2T wt - 20