# Transistor Switching Times MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Transistor Switching Times”.

1. For the BJT, β=∞, VBEon=0.7V VCEsat=0.7V. The switch is initially closed. At t=0, it is opened. At which time the BJT leaves the active region?

a) 20ms
b) 50ms
c) 60ms
d) 70ms

2. The technique used to quickly switch off a transistor is by_________
a) reverse biasing its emitter to collector junction
b) reverse biasing its base to collector junction
c) reverse biasing its base to emitter junction
d) reverse biasing any junction

3. The collector current will not reach the steady state value instantaneously because of_________
a) stray capacitances
b) resistances
c) input blocking capacitances
d) coupling capacitance

4. The disadvantage of using the method of reverse biasing base emitter junction is_________
a) high voltage control signal
b) low voltage control signal
c) output swing
d) incomplete switching of output

5. Which of the following helps in reducing the switching time of a transistor?
a) a resistor connected from base to ground
b) a resistor connected from emitter to ground
c) a capacitor connected from base to ground
d) a capacitor connected from emitter to ground

6. The switching of power with a PNP transistor is called _________
a) sourcing current
b) sinking current
c) forward sourcing
d) reverse sinking

7. Which of the following circuits helps in the applications of switching times?

a)

b)

c)

d)

8. The time taken for a transistor to turn from saturation to cut off is _________
a) inversely proportional to charge carriers
b) directly proportional to charge carriers
c) charging time of the capacitor
d) discharging time of the capacitor

9. The base emitter voltage in a cut off region is _________
a) greater than 0.7V
b) equal to 0.7V
c) less than 0.7V
d) cannot be predicted

10. Switching speed of P+ junction depends on _________
a) Mobility of minority carriers in P junction
b) Life time of minority carriers in P junction
c) Mobility of majority carriers in N junction
d) Life time of minority carriers in N junction