1. An ideal power diode must have
a) low forward current carrying capacity
b) large reverse breakdown voltage
c) high ohmic junction resistance
d) high reverse recovery time
Explanation: Large reverse breakdown voltage is desirable whereas others will increases the losses.
2. To make a signal diode suitable for high current & high voltage carrying applications with minimum losses, ________
a) a lightly doped n layer is grown between the two p & n layers
b) a heavily doped n layer is grown between the two p & n layers
c) a lightly doped p layer is grown between the two p & n layers
d) a heavily doped p layer is grown between the two p & n layers
Explanation: The above process simply the one used to manufacture power diodes.
3. Power diode is __________
a) a three terminal semiconductor device
b) a two terminal semiconductor device
c) a four terminal semiconductor device
d) a three terminal analog device
Explanation: It has two terminals anode and cathode same as that of a ordinary diode. In fact, a power diode is nothing but a signal diode with a extra layer.
4. The V-I Characteristics of the diode lie in the
a) 1st & 2nd quadrant
b) 1st & 3rd quadrant
c) 1st & 4th quadrant
d) Only in the 1st quadrant
Explanation: First in the forward region & Third in the reverse biased mode
5. Which of the following is true in case of a power diode with R load?
a) I grows almost linearly with V
b) I decays almost linearly with V
c) I is independent of V
d) I initial grows than decays
Explanation: R load therefore V and I are linear and in phase.
6. A diode is said to be reversed biased when the
a) cathode is positive with respect to the anode
b) anode is positive with respect to the cathode
c) cathode is negative with respect to the anode
d) both cathode & anode are negative
Explanation: K is positive w.r.t the A when the device is reversed biased.
7. A diode is said to be forward biased when the
a) cathode is positive with respect to the anode
b) anode is positive with respect to the cathode
c) anode is negative with respect to the anode
d) both cathode & anode are positive
Explanation: A is positive w.r.t the K when the device is forward biased.
8. In case of an ideal power diode, the leakage current flows from
a) anode to cathode
b) cathode to anode
c) in both the directions
d) leakage current does not flow
Explanation: Leakage current does not flow in IDEAL diode.
9. The peak inverse current IP for a power diode is given by the expression
a) IP=t + di/dt
b) IP=t * log i
c) IP=t * di/dt
d) IP=t * ∫ t*i dt
Explanation: The leakage current is the reveres recovery time (t) into the rate of change of current.
10. A power diode with small softness factor (S-factor) has
a) small oscillatory over voltages
b) large oscillatory over voltages
c) large peak reverse current
d) small peak reverse current
Explanation: Peak reverse current is independent of S-factor smaller the value of S-factor larger the oscillatory over voltage.