Metal Oxide Semiconductor (MOS) Transistor MCQ Quiz – Objective Question with Answer for Metal Oxide Semiconductor (MOS) Transistor

11. The Fermi potential(φfp) for the n-type MOSFET is:

A. φfp = (kT/q)ln(ND/NA.
B. φfp = (kT/q)ln(NA/ND.
C. φfp = (kT/q)ln(ND/ni)
D. φfp = (kT/q)ln(ni/ND.

Answer: C

The Fermi potential of the p-type semiconductor is φfp = (kT/q)ln(ND/ni) where ni denotes the intrinsic carrier concentration of silicon, NA is acceptor concentration, ND is Donor Concentration.

12. The principle of the MOSFET operation is:

A. Control the conduction of current between the source and the drain, using the potential difference applied at the gate voltage as a control variable
B. Control the current conduction between the source and the gate, using the electric field applied at the drain voltage as a control variable
C. Control the current conduction between the PN junction, using the electric field generated by the bias voltage as a control variable
D. Control the current conduction between the PN junctions, using the electric potential generated by the gate voltage as a control variable

Answer: A

The principle of the MOSFET operation is Control the conduction of current between the source and the drain, using the potential difference applied at the gate voltage as a control variable.

By varying the gate voltage the current between the source and drain is varied.

13. The conduction of current IDS depends on:

A. Gate to source voltage
B. Drain to source voltage
C. Bulk to source voltage
D. All of the above

Answer: D

The current depends on Vgs, Vds, Vbs, Vt, and dimensions of MOSFET.

14. The impedance at the input of the n-MOS transistor circuit is:

A. Lesser than p-MOS transistor
B. Greater than BJT transistor
C. Lesser than JFET transistor
D. Zero

Answer: B

The impedance at the input of the n-MOS transistor is more than the BJT transistor.

15. The depletion mode n-MOS differs from enhancement-mode n-MOS in:

A. Threshold voltage
B. Channel Length
C. Switching time
D. None of the mentioned

Answer: A

If n-MOS operates with negative threshold voltage then it is in depletion mode. If n-MOS operates with positive threshold voltage then it is in enhancement mode.

16. The n-MOS invertor is better than BJT in terms of:

A. Fast switching time
B. Low power loss
C. Smaller overall layout area
D. All the mentioned

Answer: D

The n-MOS invertor is better than BJT inverter due to its fast switching time, low power loss, and smaller overall layout area.

17. The n-MOS inverter consists of an n-MOS transistor is driven and

A. Resistor as a load
B. Depletion mode n-MOS as a load
C. Enhancement mode n-MOS as a load
D. Any of the mentioned

Answer: D

The n-MOS inverter consists of n-MOS and resistor or depletion mode n-MOS or enhancement mode n-MOS at the pull-up load.

18. If the n-MOS and p-MOS of the CMOS inverters are interchanged the output is measured at:

A. Source of both transistor
B. Drains of both transistor
C. Drain of n-MOS and source of p-MOS
D. Source of n-MOS and drain of p-MOS

Answer: A

When the transistors are interchanged, The drain of n-MOS is connected to the supply voltage, and the drain of p-MOS is connected to the ground. The output is measured at the source of both the transistors.

19. What will be the effect on output voltage if the positions of n-MOS and p-MOS in the CMOS inverter circuit are exchanged?

A. Output is the same
B. Output is reversed
C. Output is always high
D. Output is always low

Answer: B

When the input is low, P-MOS is ON and the output is pulled down to the ground. When the input is high, n-MOS is ON and the output is pulled up to the supply voltage.

20. The average power dissipated in resistive load n-MOS inverter is:

A. 0
B. VDD (VDD-VOL)/R
C. VDD (VDD-VOL)/2R
D. VDD (VDD-VIH)/2R

Answer: C

When the input voltage is equal to VOH on the other hand, both the driver MOSFET and the load resistor conduct a nonzero current. Since the output voltage, in this case, is equal to VOL, the DC power consumption of the inverter can be estimated as VDD (VDD-VOL)/2R.

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