GATE 1998 ECE Video Solutions on EDC (Electronic Devices and Circuits)

1. The electron and hole concentrations in a intrinsic semiconductor are n_i and p_i respectively. When doped with a P-type material, these changes to n and p respectively. Then
a. n + P = n_i + P_i
b. n + n_i = p + p_i
c. np_i = n_ip
d. np = n_ip_i

Answer: D

Solution : https://www.youtube.com/watch?v=Zm31Ob0KekU


2. The static characteristic of an adequately forward biased PN junction is a straight line, if the plot is of
a. Log I vs. log V
b. Log I vs. V
c. I vs. log V
d. I vs. V

Answer: B

Solution : https://www.youtube.com/watch?v=dsHsIn6LSls


3. A long specimen of p-type semiconductor material
a. Is positively charged
b. Is electrically neutral
c. Has an electric field directed along its length
d. Acts as a dipole

Answer: B

Solution : https://www.youtube.com/watch?v=CMnmcekH-3g


4. Two identical FETs, each characterized by the parameters g_m and r_d are connected in parallel. The composite FET is then characterized by the parameters
a. g_m/2 and 2r_d
b. g_m/2 and r_d/2
c. 2g_m and r_d/2
d. 2g_m and 2r_d

Answer: C

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


5. The units of (q/KT) are
a. V
b. V^-1
c. J
d. J/K

Answer: B

Solution : https://www.youtube.com/watch?v=DQYndoxV0ps


6. The threshold voltage for each transistor in figure is 2 volts._i must take the values

For this circuit to work as an inverter, V
a. -5 volts and 0 volts
b. -5 volts and 5 volts
c. 0 volts and 3 volts
d. 3 volts and 5 volts

Answer: A

Solution : https://www.youtube.com/watch?v=pHfKL4yw4Ko


7.. The JFET in the circuit of figure is characterized by the parameters I_DSS = 4 mA and V_p = -4 volts. Find (a) V_o if V_i = 0 and (b) V_i if V_o = 0

Answer: (a) V_o = - V_GS when V_i = 0 volts, and (b) V_i = 0.5 volts when V_o = 0 volts

Solution : https://www.youtube.com/watch?v=_5yCMN_4xO0