FPSC Assistant Executive Engineer (Electrical) Test

Electronics
(Maximum questions copied from Electronic Principles by Albert Malvino)

1. When the diode current is large, the bias is
a. Forward ✓
b. Inverse
c. Poor
d. Reverse

2. If the series resistance increases in an unloaded zener regulator, the zener current
a. Decreases ✓
b. Stays the same
c. Increases

3. If the load resistance increases in a zener regulator, the zener current
a. Decreases
b. Stays the same
c. Increases ✓

4. The device associated with voltage controlled capacitance is a
a. Light-emitting diode
b. Photodiode
c. Varactor diode ✓
d. Zener diode

5. To isolate an output circuit from an input circuit, which is the device to use?
a. Back diode
b. Optocoupler ✓
c. Seven-segment indicator
d. Tunnel diode

6. If the base supply voltage increases, the Q point moves
a. Down
b. Up ✓
c. Nowhere
d. Off the load line

7. The average d.c. output voltage for a half-wave rectifier is 13.05 V. Average value for a full-wave rectifier will be.
a. 26.1 ✓
b. 10
c. 20.16

8. The major advantage of a photo-transistor as compared to a photo-diode is its
a. Response to higher frequencies
b. AC operation
c. Increased sensitivity ✓
d. Durability

9. When transistors are used in digital circuits they usually operate in the:
a. active region
b. breakdown region
c. saturation and cutoff regions ✓
d. linear region

10. Power amplifiers in high frequency applications are mainly used
a. as a switch ✓
b. for amplification
c. none of these

11. Input impedance of an inverting OP-AMP is
a. zero
b. infinity ✓
c. 10 MΩ