Silicon Controlled Rectifiers MCQs with Explanations

An SCR (Silicon Controlled Rectifier) is made of silicon . Silicon is the primary semiconductor material used in the fabrication of SCRs due to its favorable electrical properties, including high temperature tolerance, stability, and reliability. SCRs are widely utilized in electronic devices and power control applications for their ability to handle high voltages and currents effectively. Therefore, the correct answer is Option B: Silicon.

If the firing angle in an SCR (Silicon Controlled Rectifier) circuit is increased, the output is decreased . The firing angle refers to the delay angle between the triggering signal and the conduction of the SCR. By increasing the firing angle, the SCR is triggered later in each cycle of the AC input voltage. This results in a shorter conduction period and therefore a decreased output from the SCR. Therefore, the correct answer is Option C: Is decreased.

Gate is the correct answer to “When SCR starts conducting, then ___________ loses all control”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Current is the correct answer to “An SCR is a ___________ triggered device”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Positive or negative half-cycles is the correct answer to “An SCR can exercise control over ___________ of a.c. supply”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Positive is the correct answer to “In the normal operation of an SCR, anode is ___________ w.r.t. cathode”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Three is the correct answer to “An SCR has ___________ pn junctions”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Positive is the correct answer to “In normal operation of an SCR, gate is ___________w.r.t. cathode”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Unidirectional is the correct answer to “An SCR behaves as a ___________ switch”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Gas-filled triode is the correct answer to “An SCR is a solid state equivalent of ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Changing gate voltage is the correct answer to “In an SCR circuit, the angle of conduction can be changed by ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Appropriate gate current is the correct answer to “The normal way to turn on a SCR is by ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Reducing anode voltage to zero is the correct answer to “An SCR is turned off by ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

1 V is the correct answer to “When an SCR is turned on, the voltage across it is about ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Gate is the correct answer to “The control element of an SCR is ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Cathode, anode, gate is the correct answer to “An SCR has three terminals viz ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Has small leakage current is the correct answer to “An SCR is made of silicon and not germanium because silicon”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Two SCRs in parallel opposition is the correct answer to “We can control a.c. power in a load by connecting ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Less than is the correct answer to “In an SCR circuit the supply voltage is generally ___________ that of breakover voltage”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Anode current is reduced to zero is the correct answer to “An SCR is turned off when ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Is decreased is the correct answer to “If gate current is increased, then anode-cathode voltage at which SCR closes ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Small leakage current is the correct answer to “When SCR is OFF, the current in the circuit is ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Thyristor is the correct answer to “An SCR is sometimes called ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

Four is the correct answer to “An SCR has ___________ semiconductor layers”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.

A rectifier and transistor is the correct answer to “An SCR combines the features of ___________”. This question is standard in competitive examination syllabi for Silicon Controlled Rectifiers.