Explore topic-wise MCQs in Electronics.

This section includes 33 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.

1.

Which is the seven-segment display?

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
2.

Which is the TRIAC?

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
3.

Which is the DIAC?

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
4.

The silicon-controlled rectifier (SCR) is a three-layer device consisting of a gate, an anode, and a cathode.

A. 1
B.
Answer» C.
5.

A transducer does not convert energy from one form to another.

A. 1
B.
Answer» C.
6.

SCRs are four-layer devices that are either fully conducting or not conducting.

A. 1
B.
Answer» B.
7.

A DIAC is a bidirectional diode that has a symmetrical switching mode.

A. 1
B.
Answer» B.
8.

A semiconductor using the hall effect will detect magnetic fields.

A. 1
B.
Answer» B.
9.

A TRIAC will control AC voltage during the positive half cycle only.

A. 1
B.
Answer» C.
10.

A TRIAC can be triggered or activated by either a positive or a negative input gate trigger.

A. 1
B.
Answer» B.
11.

A silicon-controlled rectifier (SCR) has 3 terminals labeled base, collector, and emitter.

A. 1
B.
Answer» C.
12.

An optically coupled isolator is a device containing _________ in a single package.

A. a photodiode and an optotransmitter
B. an LED and an SCR
C. an anode and a cathode
D. an IRED and a silicon phototransistor
Answer» E.
13.

To turn an SCR off, simply remove the gate voltage.

A. 1
B.
Answer» C.
14.

The gate of a TRIAC can turn it on to have current flow in either direction.

A. 1
B.
C. 1
D.
Answer» B.
15.

A thermistor is a semiconductor device that acts like a piezoresistive resistor.

A. 1
B.
Answer» C.
16.

What type of application would use an injection laser diode?

A. a 10BASE-T Ethernet
B. a liquid crystal display
C. a fiber optic transmission line
D. a good flashlight
Answer» D. a good flashlight
17.

A photodiode is a device that produces light.

A. 1
B.
Answer» C.
18.

The DIAC conducts in only one direction when gated on.

A. 1
B.
C. 1
D.
Answer» C. 1
19.

What type of application would use a photovoltaic cell?

A. an automobile horn
B. a TI 92 calculator
C. a magnetic field detector
D. a remote power source
Answer» E.
20.

The DIAC is a:

A. transistor
B. unidirectional device
C. three-layer device
D. bidirectional device
Answer» E.
21.

Once a DIAC is conducting, the only way to turn it off is with:

A. a positive gate voltage
B. a negative gate voltage
C. low-current dropout
D. breakover
Answer» D. breakover
22.

A transducer's function is to:

A. transmit electrical energy
B. convert energy
C. produce mechanical energy
D. prevent current flow
Answer» C. produce mechanical energy
23.

What is an SCR?

A. a PNPN thyristor with 3 terminals
B. a PNPN thyristor with 4 terminals
C. a PNP thyristor with 3 terminals
D. an NPN thyristor with 3 terminals
Answer» B. a PNPN thyristor with 4 terminals
24.

The only way to close an SCR is with:

A. a trigger input applied to the gate
B. forward breakover voltage
C. low-current dropout
D. valley voltage
Answer» C. low-current dropout
25.

What does a hall effect sensor sense?

A. temperature
B. moisture
C. magnetic fields
D. pressure
Answer» D. pressure
26.

When checking a good SCR or TRIAC with an ohmmeter it will:

A. show high resistance in both directions
B. show low resistance with positive on anode and negative on cathode, and high resistance when reversed
C. show high resistance with negative on anode and positive on cathode, and low resistance when reversed
D. show low resistance in both directions
Answer» B. show low resistance with positive on anode and negative on cathode, and high resistance when reversed
27.

The TRIAC is equivalent to ________________.

A. a four-layer diode
B. two DIACs in parallel
C. a thyristor with a gate lead
D. two SCRs in parallel
Answer» E.
28.

The PUT (programmable unijunction transistor) is actually a type of:

A. UJT thyristor
B. FET device
C. TRIAC
D. SCR
Answer» B. FET device
29.

What causes the piezoelectric effect?

A. heat or dissimilar metals
B. pressure on a crystal
C. water running on iron
D. a magnetic field
Answer» C. water running on iron
30.

The smallest amount of current that the cathode-anode can have, and still sustain conduction of an SCR is called the:

A. maximum forward current
B. maximum forward gate current
C. holding current
D. reverse gate leakage current
Answer» E.
31.

The optically coupled isolator interrupter module is used to transfer switching information between two electrically isolated points.

A. 1
B.
C. 1
D.
Answer» C. 1
32.

A UJT has:

A. two base leads
B. one emitter lead
C. two emitter leads and one base lead
D. one emitter lead and two base leads
Answer» E.
33.

A TRIAC:

A. can trigger only on positive gate voltages
B. can trigger only on negative gate voltages
C. cannot be triggered with gate voltages
D. can be triggered by either a positive or a negative gate voltage
Answer» E.