Question

For the following circuit and given that R1 29.6 k, R2 4 k, R3 16.4 k, R4-30 kΩ 2 Vin out Determine the Gain of the system (G-Vout/Vin). 8.4 Determine the output voltage if Vin(t) 80.1 mV. 0.673 Submit Answer

Answer 1

Re-draw the circuit diagram with node voltages. 1 29.6 k 2 16.4 k 2 R3 WWW 4 k2 R4 30k12 sout Figure 1 According to virtual ground concept, the voltage at the inverting terminal is equal to voltage at non-inverting terminal. VA =- Vin VB = 0 V(ground) No current enters into op-amp. Thus, the current in resistor R, R2 and Rz are equal.

Re-draw the circuit diagram with loop direction. 29.6 kg 16.4k2 R, R3 4 ke2 R4 30k2 Figure 2 From Figure 2, determine the expression for current I. I-VA - VB - 4k Put VA =-Vin and VB = 0 V. Thus, 1 = - Vin - 0 4k Vin 13 Ak

4k Apply Kirchhoff's voltage law around the loop. I(29.6 k)+1(4 k)+1(16.4 k) - Vout = 0 I(50 k) – Vout = 0 Put 1 = - Vin Therefore, (*)(50 k) – Vour = 0 (- Vin)(12.5) - Vout = 0 Vout = -12.5Vin Vout = -12.5 Therefore, the gain is G = Yout =-12.5 Vin Determine the output voltage, Vin (t) = 80.1 mV. Vout = -12.5 out 80.1*10-3 =-12.5 Vout = (-12.5)(80.1x10-) Vout =-1.00125 V