1
GATE ECE 2017 Set 2
Numerical
+2
-0
In the circuit shown, transistors Q1 and Q2 are biased at a collector current of 2.6 mA. Assuming that transistor current gains are sufficiently large to assume collector current equal to emitter current and thermal voltage of 26m V, the magnitude of voltage gain Vo/Vs in the mid-band frequency range is _____________ (up to second decimal place).
2
GATE ECE 2017 Set 1
Numerical
+2
-0
For the DC analysis of the Common-Emitter amplifier shown, neglect the base current and assume that the emitter and collector current are equal. Given that VT = 25mV, VBE = 0.7V, and the BJT output r0 is practically infinite. Under these conditions the midband voltage gain magnitude, av = $$\left| {{v_0}/{v_i}} \right|\,\,\,V/V,$$ is _____
3
GATE ECE 2017 Set 1
Numerical
+2
-0
In the figure shown, the npn transistor acts as a switch.

For the input vin(t)as shown in the figure, the transistor switches between the cut-off and saturation regions of operation, when T is large. Assume collector-to-emitter voltage saturation VCE(sat) = 0.2V and base-to-emitter voltage VBE = 0.7V. The minimum value of the common-base current gain$$\left( \alpha \right)$$ of the transistor for the switching should be _________.

4
GATE ECE 2015 Set 2
Numerical
+2
-0
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 _______.