SCR MCQ – Silicon Controlled Rectifier Multiple Choice Questions

SCR MCQs

Names of Terminals of SCR

SCR has three terminals namely the:

1. Anode, Base, Cathode
2. Anode, Cathode, Gate
3. Anode, Cathode, Drain
4. Anode, Base, Drain

Correct answer: 2. Anode, cathode, gate

SCR Behavior as Uni or Bidirectional

An SCR behaves as

1. Unidirectional switch
2. Bidirectional switch
3. Mechanical
4. None of the above

Correct answer: 1. Unidirectional switch

Most applications of the SCR are for AC power control, despite the fact that SCRs are inherently DC (unidirectional) devices.

The only two terminals of SCR showing any continuity between them at all should be

The only two terminals of SCR showing any continuity between them at all should be

1. Gate and cathode
2. Gate and anode
3. Anode and cathode
4. Anode and Gate

Correct answer: 1. Gate and cathode

Also Read: SCR terminal identifiation using Ohmmeter

The number of PN junctions on SCR

An SCR has ___________ pn junctions

1. One
2. Two
3. Three
4. Four

Correct answer: 3. Three

Which of the following is correct about the reverse firing of SCR

Which of following is correct about reverse firing of SCR

1. Reverse-firing is only sometimes effective
2. Reverse-firing is always effective
3. Reverse-firing is most effective method

Correct answer: 1. Reverse-firing is only sometimes effective

SCRs may be fired by intentional triggering of the gate terminal, excessive voltage (breakdown) between anode and cathode, or excessive rate of voltage rise between anode and cathode. SCRs may be turned off by anode current falling below the holding current value (low-current dropout), or by “reverse-firing” the gate (applying a negative voltage to the gate). Reverse-firing is only sometimes effective, and always involves high gate current. Continue Reading here

During the normal operation of an SCR the gate is

During the normal operation of an SCR the gate is

1. Negative w.r.t. cathode
2. Positive w.r.t. cathode
3. At zero potential
4. None of the above

Correct answer: 2. Positive w.r.t. cathode

The angle of conduction in SCR circuit can be varied by

The angle of conduction in SCR circuit can be varied by

1. Changing anode voltage
2. Changing gate voltage
3. Reverse biasing the gate
4. None of the above

Correct answer: 2. Changing gate voltage

An SCR is fabricated from silicon and not germanium due to reason being

An SCR is fabricated from silicon and not germanium due to reason being

1. Silicon has small leakage current
2. Silicon is inexpensive
3. Silicon is mechanically strong
4. Silicon is tetravalent

Correct answer: 1. Silicon has small leakage current

The number of semiconductor layers on SCR are

The number of semiconductor layers on SCR are

1. Two
2. Three
3. Four
4. None of the above

Correct answer: 3. Four

AC power in a load can be controlled by connecting

AC power in a load can be controlled by connecting

1. Two SCRs in series
2. Two SCRs in parallel
3. Two SCRs in parallel opposition
4. None of the above

Correct answer: 3. Two SCRs in parallel opposition