Explore topic-wise MCQs in Electronic Devices Circuits.

This section includes 5 Mcqs, each offering curated multiple-choice questions to sharpen your Electronic Devices Circuits knowledge and support exam preparation. Choose a topic below to get started.

1.

One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their

A. Noise figure increases
B. Transit time becomes too short
C. Shunt capacitive reactances become too large
D. Series inductive reactances become too small
Answer» B. Transit time becomes too short
Discussion
2.

According to the tunneling phenomenon of tunnel diode which one of the following is true?

A. Width of the junction barrier varies as the square root of impurity concentration.
B. Width of the junction barrier varies as the impurity concentration.
C. Width of the junction barrier varies inversely as the square root of impurity concentration.
D. Width of the junction barrier varies as the cube root of impurity concentration.
Answer» D. Width of the junction barrier varies as the cube root of impurity concentration.
Discussion
3.

An MOS capacitor with P substrate is in accumulation mode. The dominant change in the channel is due to the presence of ______.

A. electrons
B. negatively charged ions
C. holes
D. positively charged ions
Answer» D. positively charged ions
Discussion
4.

A voltage \(\rm V_G\) is applied across a MOS capacitor with metal gate and p-type silicon substrate at \(\rm T=300 \ K\). The inversion carrier density (in number of carriers per unit area) for \(\rm V_G = 0.8 \ V\) is \(\rm 2 × 10^{11} cm^{−2}\). For \(\rm V_G = 1.3 \ V\), the inversion carrier density is \(\rm 4 × 10^{11} cm^{−2}\). What is the value of the inversion carrier density for \(\rm V_G = 1.8 \ V\)?

A. \(\rm 4.5 × 10^{11} cm^{−2}\)
B. \(\rm 6 × 10^{11} cm^{−2}\)
C. \(\rm 7.2 × 10^{11} cm^{−2}\)
D. \(\rm 8.4 × 10^{11} cm^{−2}\)
Answer» C. \(\rm 7.2 × 10^{11} cm^{−2}\)
Discussion
5.

If fixed positive charges are present in the gate oxide of an n-channel enhancement type MOSFET it will lead to

A. a decrease is the threshold voltage
B. channel length modulation
C. an increase in substrate leakage current.
D. an increase in accumulation capacitance.
Answer» B. channel length modulation
Discussion