**GATE 2015 ECE – Questions on Analog Circuits with Answers**

1. In the circuit shown, assume OP-AMP is ideal then the 3 dB cut off frequency (in Hz) is __________

**Solution:**https://www.youtube.com/watch?v=68aTpkiHA6c

2. Consider the bode plot shown in figure. Assume that all the poles and zeros are real valued. The value of f

_{H}– f

_{L}(in Hz) is _____________

**Solution:**https://www.youtube.com/watch?v=R95T4ztuNQo

3. At very high frequencies, the peak output voltage V

_{o}(in volts) is ______________

**Solution:**https://www.youtube.com/watch?v=_O4UfZGA87c

4. In the circuit shown, assume that the OP-AMP is ideal. If the gain (V

_{o}/V

_{in}) is –12 , then the value of R (in kΩ) is _________________

**Solution:**https://www.youtube.com/watch?v=tK6-rhSk62w

5. Negative feedback in a closed loop control system DOES NOT

a. Reduce the overall gain

b. Reduce bandwidth

c. Improve disturbance rejection

d. Reduce sensitivity to parameter variation

**Solution:**https://www.youtube.com/watch?v=TFCXqD_Tu4s

6. In the circuit shown, assume that the OP-AMP is ideal. The bridge output voltage V

_{o}(in mV) for δ = 0.05 is _______________

**Solution:**https://www.youtube.com/watch?v=j3isPwGHe_8

7. The circuit shown in the figure has an ideal OP-AMP. The oscillation frequency and the condition to sustain the oscillations respectively are ________________

**Solution:**https://www.youtube.com/watch?v=SA30jnkdunM

8. In the circuit shown, I

_{1}= 80 mA and I

_{2}= 4 mA. Transistors T

_{1}and T

_{2}are identical. Assume that thermal voltage is 26 mV at 27

^{o}C. At 50

^{o}C, the value of voltage V

_{12}= V

_{1}– V

_{2}(in mV) is _______________

**Solution:**https://www.youtube.com/watch?v=vltaQSRU2KE

9. In the circuit shown, V

_{o}= V

_{OA}for switch SW in position A and V

_{o}= V

_{OB}for switch SW in position B. Assume that the OP-AMP is ideal. The value of V

_{OB}/V

_{OA}is ______________

**Solution:**https://www.youtube.com/watch?v=c4GkgCOXgLQ

10. If the circuit shown has to function as a clamping circuit, then which one of the following conditions should be satisfied for the sinusoidal signal of period T?

**Solution:**https://www.youtube.com/watch?v=POqJ5VOSIdk

11. In the bistable circuit shown, the ideal OP-AMP ahs saturation levels of ± 5 volts. The value of R1 (in kΩ) that gives a hysteresis width of 500 mV is _________________

**Solution:**https://www.youtube.com/watch?v=Q6RQWfpg_6c

12. In the ac equivalent circuit shown, the two BJTs are biased in active region and have identical parameters with β>>1. The open circuit small signal voltage gain is approximately is _________________

**Solution: https://youtu.be/Jod5sADhRa4**

13. Assuming that the OP-AMP in the circuit shown is ideal, the output voltage V

_{o}(inn volts) is __________

**Solution:**https://www.youtube.com/watch?v=3RL9Dy8Xxco

14. For the voltage regulator circuit shown,the input voltage (V

_{in}) is 20 V ± 20% and the regulated output voltage (V

_{out}) is 10 volts. Assume the OP-AMP is ideal. For a load R

_{L}drawing 200 mA, the maximum power dissipation in Q

_{1}(in Watts) is _________________

**Solution:**https://www.youtube.com/watch?v=cKkJa1-Kl_U