1. Which of the following can be used for providing high gain?
A. transistor
B. Darlington transistor pair
C. resistor
D. capacitor
Answer: b
The Darlington pair of transistors can provide high gain than a single transistor. This is one of the methods used to avoid voltage mismatches that the system produces. By using high gain transistors the voltage mismatches can be reduced upto a limit.
2. Which devices have high drive capability?
A. transistor
B. fet
C. buffer pack
D. Darlington amplifier
Answer: c
The buffer pack is used to avoid the voltage mismatches which possess a high drive capacity and it can also provide high drive currents than the normal logic outputs.
3. Which of the following is used to switch heavy loads?
A. fet
B. transistor
C. buffer pack
D. Darlington pair
Answer: a
The field-effect transistor can be used to provide a very high effective gain and hence they can be used to switch heavy loads easily from a logic device. These are also voltage-controlled transistors.
4. Which allows the switching of DC motor by using two outputs and four FETs?
A. transistor
B. H bridge
C. Darlington pair
D. buffer pack
Answer: b
The H bridge can be created by using several switches which allows a DC motor to be switched on and reversed in the direction. The switching can be done by using two outputs and four FETs.
5. Which of the following is used to create the H bridge?
A. switches
B. led
C. capacitor
D. inductor
Answer: a
The H bridge can be created by using several switches. This allows a DC motor to be switched on and reversed in the direction and the switching of the DC motor can be done by using two outputs and four FETs.
6. Which of the following allows voltage reversing?
A. H bridge
B. Relays
C. LEDs
D. LCDs
Answer: A
The H bridge is used in controlling DC motors or any other loads which need voltage reversing.
7. Which devices are used as indicators in a digital system?
A. LCD
B. LED
C. Varactor diode
D. Gunn diode
Answer: b
The light-emitting diodes are used as indicators in the digital system and can be directly driven by a logic output.
8. How is the biasing done in LEDs?
A. forward bias
B. no bias
C. supply voltage
D. reverse bias
Answer: d
The LEDs will light up only when the diode reverse breakdown is achieved. It is usually about 2 to 2.2V.
9. Which of the following determines the brightness of LEDs?
A. current
B. voltage
C. resistance
D. conductance
Answer: A
The current drive determines the brightness of the LEDs and it is usually associated with a current limiting resistor in series with the LED to prevent the overheating.
10. Which of the following is a current limiting device?
A. voltage
B. current
C. buffer
D. inductor
Answer: C
A buffer can be used as a current limiting device. Similarly, a transistor can also be used as a current limiting device.
