1
GATE ECE 2017 Set 2
Numerical
+2
-0
In the voltage reference circuit shown in the figure, the op-amp is ideal and the transistors Q1, Q2,….., Q32 are identical in all respects and have infinitely large values of common – emitter current gain $$\beta$$. The collector current (IC) of the transistors is related to their base emitter voltage (VBE) by the relation IC = IS exp (VBE/VT); where Is is the saturation current. Assume that the voltage VP shown in the figure is 0.7 V and the thermal voltage VT=26mV

The output voltage Vout (in volts) is _____.

2
GATE ECE 2017 Set 1
Numerical
+2
-0
The amplifier circuit shown in the figure is implemented using a compensated operational amplifier (op-amp), and has an open-loop voltage gain, A0 105 V/V and an open-loop cut-off frequency, fC = 8 Hz. The voltage gain of the amplifier at 15 kHz, in V/V, is __________.
3
GATE ECE 2016 Set 3
Numerical
+2
-0
For the circuit shown in the figure, R1 = R2 = R3 = 1 Ω, L = 1 µH and C = 1 µF. If the input Vin = cos(106t) , then the overall voltage gain (Vout /Vin) of the circuit is __________.
4
GATE ECE 2016 Set 2
Numerical
+2
-0
In the opamp circuit shown, the Zener diodes Z1 and Z2 clamp the output voltage Vo to +5 V or -5 V. The switch S is intially closed and is opened at time t = 0

The time t = t1 (in seconds) at which Vo changes state is _____.