GATE 1989 ECE Analog Circuits (Analog Electronics) - Video Solutions

1. Referring to the figure shown,

Answer: B & C

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


2. Of the four biasing circuits shown in figure, for a BJT, indicate the one which can have maximum bias stability

Answer: A

Solution : https://www.youtube.com/watch?v=yvA3x-0ljUo


3. The feedback amplifier shown in figure has

a. Current – Series feedback with large input impedance and large output impedance
b. Voltage – Series feedback with large input impedance and low output impedance
c. Voltage – Shunt feedback with low input impedance and low output impedance
d. Current – Shunt feedback with low input impedance and low output impedance

Answer: C

Solution : https://www.youtube.com/watch?v=K4UNqioWiXE

GATE 1989 Video Solutions on Digital Circuits

1. Among the digital IC families, ECL, TTL and CMOS :
a. ECL has the least propagation delay
b. TTL has the largest fan-out
c. CMOS has the biggest noise margin
d. TTL has the lowest power consumption

Answer: A & C

Solution : https://www.youtube.com/watch?v=ArQwYJ0bO-I


2. A logic family has threshold voltage of 2 volts, minimum guaranteed output high voltage V_OH = 4 volts, minimum accepted input high voltage V_IH = 3 volts, maximum guaranteed output low voltage V_OL = 1 volt, and maximum accepted input low voltage V_IL = 1.5 volts. Its noise margin is
a. 2 volts
b. 1 volts
c. 1.5 volts
d. 0.5 volts

Answer:D

Solution : https://www.youtube.com/watch?v=q10wmlZk97w



3. Indicate which of the following logic gates can be used to realized all possible combinational logic functions :
a. OR gates only
b. NAND gates only
c. EX-OR gates only
d. NOR gates only

Answer:B & D

Solution : https://www.youtube.com/watch?v=zOkL4jMirYM

GATE 1989 Video Solutions on EDC (Electronic Devices and Circuits)

1.       Due to illumination by light, the electron and hole concentrations in a heavily doped N-type semiconductor increases by Δn and Δp respectively, if n_i is the intrinsic carrier concentration then

a.       Δn < Δp

b.      Δn > Δp

c.       Δn = Δp

d.      Δn x Δp = n_i²

Answer:C

                 Solution : https://www.youtube.com/watch?v=Kdb4wbs7aoQ

2.       The concentration of ionized acceptors and donors in a semiconductor are N_A, N_D respectively. If N_A > N_D and n_i is the intrinsic  concentration, then the position of the Fermi level with respect to the intrinsic level depends on

a.       N_A – N_D

b.      N_A + N_D

c.       (N_A x N_D) / n_i²

d.      n_i

Answer:A

                 Solution :  https://www.youtube.com/watch?v=fncmLfR38V0

3.       The switching speed of P⁺N junction depends primarily on

a.       the mobility of minority carriers in the P⁺ region

b.      the lifetime of minority carriers in the P⁺ region

c.       the mobility of majority carriers in the N region

d.      the lifetime of majority carriers in the N region

Answer:B

                 Solution :  https://www.youtube.com/watch?v=vPptctf8wSU

4.       In a Zener diode,

a.       only P-region is heavily doped

b.      only N-region is heavily doped

c.       both P and N-regions are heavily doped

d.      both P and N-regions are lightly doped

Answer:C

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

5.       In a MOSFET, the polarity of the inversion layer is the same as that of the

a.       Charge on the gate electrode

b.      Minority carriers in the drain

c.       Majority carriers in the substrate

d.      Majority carriers in the source

Answer:D

                 Solution :   https://www.youtube.com/watch?v=EoJQBXa0NT0