GATE 1999 ECE Video Solutions on EDC (Electronic Devices and Circuits)

1. The early effect in a bipolar junction transistor is caused by
a. Fast turn ON
b. Fast turn OFF
c. Large Collector – Base reverse bias
d. Large Emitter – Base forward bias

Answer: C

Solution: www.youtube.com/watch?v=QsIqgVPIAxU


2. In the cascode amplifier shown in figure, if the common emitter stage (Q₁) has a Transconductance of g_m1 and the common base stage (Q₂) has Transconductance of g_m2, then the overall Transconductance g = I_o / V_i of the cascode amplifier is

a. g_m1
b. g_m2
c. g_m1/2
d. g_m2/2

Answer: A

Solution : https://www.youtube.com/watch?v=S4DaucXo7Uo


3. An n-channel JFET has I_DSS = 2 mA and V_p = -4 volts. Its Transconductance g_m in mS for an
applied gate to source voltage of -2 volts is
a. 0.25
b. 0.50
c. 0.75
d. 1.0

Answer: B

Solution : https://www.youtube.com/watch?v=ANQD8vJtkw8


4. A DC power supply has a no-load voltage of 30 volts, and a full load voltage of 25 volts at a full
load current of one amp. Its output resistance and load regulation, respectively are
a. 5 Ω and 20 %
b. 25 Ω and 20 %
c. 5 Ω and 16.7 %
d. 25 Ω and 16.7 %

Answer: B

Solution : https://www.youtube.com/watch?v=cgv8J_E_FqY


5. In the CMOS inverter circuit shown in figure, the input V_i makes a transition from V_OL (= 0 volts) to V_OH (= 5 volts). Determine the High to Low propagation delay time (tp_HL) when it is driving a capacitive load (C_L) of 20 pF.
Device data :

Answer: 0.156 µSec

Solution : https://www.youtube.com/watch?v=0t8YIeh7E_0