Electronics-Diodes and Applications
Electronics-Diodes and Applications
1. What is a varistor?
- a voltage-dependent resistor
- a voltage-dependent diode
- a current-dependent resistor
- a current-dependent diode
2. Which type of transformer is required to create a 180 degree input to a rectifier?
- center-tapped secondary
- step-down secondary
- stepped-up secondary
- split winding primary
3. What circuit activity may shift a characteristic curve so that diode operating points are different?
- higher power (heat)
- higher resistance
- lower voltage
- lower current
4. The dc current through each diode in a bridge rectifier equals:
- the load current
- half the dc load current
- twice the dc load current
- one-fourth the dc load current
5. When matching polarity connections have been made and the potential difference (PD) is above 0.7 V, the diode is considered to be:
- not working
- forward biased
- reverse biased
- an open switch
6. In a power supply diagram, which block indicates a smooth dc output?
- transformer
- filter
- rectifier
- regulator
7. If a 169.7 V half-wave peak has an average voltage of 54 V, what is the average of two full-wave peaks?
- 119.9 V
- 108.0 V
- 115.7 V
- 339.4 V
8. The characteristic curve for the complex model of a silicon diode shows that
- the barrier potential is 0 V
- the barrier potential stays fixed at 0.7 V
- the barrier potential increases slightly with an increase in current
- the barrier potential decreases slightly with an increase in current
9. Since diodes are destroyed by excessive current, circuits must have:
- higher voltage sources
- current limiting resistors
- more dopants
- higher current sources
10. A diode for which you can change the reverse bias, and thus vary the capacitance is called a
- varactor diode
- tunnel diode
- zener diode
- switching diode