1. In resistive region __________
a) Vds greater than (Vgs – Vt)
b) Vds lesser than (Vgs – Vt)
c) Vgs greater than (Vds – Vt)
d) Vgs lesser than (Vds – Vt)
Explanation: In non saturated or resistive region, Vds lesser than Vgs – Vt where Vds is the voltage between drain and source, Vgs is the gate-source voltage and Vt is the threshold voltage.
2. What is the condition for saturation?
a) Vgs = Vds
b) Vds = Vgs – Vt
c) Vgs = Vds – Vt
d) Vds > Vgs – Vt
Explanation:The condition for saturation is Vds = Vgs – Vt since at this point IR drop in the channel equals the effective gate to channel voltage at the drain.
3. Threshold voltage is negative for __________
a) nMOS depletion
b) nMOS enhancement
c) pMOS depletion
d) pMOS enhancement
Explanation: The threshold voltage for nMOS depletion denoted as Vtd is negative.
4. The current Ids _______ as Vds increases.
a) increases
b) decreases
c) remains fairly constant
d) exponentially increases
Explanation: The current Ids remains fairly constant as Vds increases in the saturation region.
5. In linear region ______ channel exists.
a) uniform
b) non-uniform
c) wide
d) uniform and wide
Explanation: In linear region of MOSFET, the channel is uniform and narrow. This is the concentration distribution.
6. . When the channel pinches off?
a) Vgs > Vds
b) Vds > Vgs
c) Vds > (Vgs-Vth)
d) Vgs > (Vds-Vth)
Explanation: In MOSFET, in saturation region, when Vds > (Vgs – Vth), the channel pinches off that is the channel current at the drain spreads out
7. When the threshold voltage is more, leakage current will be?
a) more
b) less
c) all of the mentioned
d) none of the mentioned
Explanation: Increasing the threshold voltage, leads to small leakage current when turned off and reduces current flow when turned on.
8. MOSFET is used as ___________
a) current source
b) voltage source
c) buffer
d) divider
Explanation: MOSFET is used as current source. Bipolar junction transistor also acts as good current source
9. The work function difference is negative for ____________
a) silicon substrate
b) polysilicon gate
c) silicon substrate & polysilicon gate
d) none of the mentioned
Explanation: The work function difference between gate and Si (Φms) is negative for silicon substrate and polysilicon gate
10. Substrate bias voltage is positive for nMOS.
a) true
b) false
Explanation: Substrate bias voltage Vsb is positive for pMOS and negative for nMOS.