Key Topic 23: SCRs, TRIACS

Question 1

3-23C1: How might two similar SCRs be connected to safely distribute the power load of a circuit?

A. In series.
B. In parallel, same polarity.
C. In parallel, reverse polarity.
D. In a combination series and parallel configuration.

Answer 1

C. In parallel, reverse polarity.

Question 2

3-23C2: What are the three terminals of an SCR?

A. Anode, cathode, and gate.
B. Gate, source, and sink.
C. Base, collector, and emitter.
D. Gate, base 1, base 2.

Answer 2

A. Anode, cathode, and gate.

Question 3

3-23C3: Which of the following devices acts as two SCRs connected back to back, but facing in opposite directions and sharing a common gate?

A. JFET.
B. Dual-gate MOSFET.
C. DIAC.
D. TRIAC.

Answer 3

D. TRIAC.

Question 4

3-23C4: What is the transistor called that is fabricated as two complementary SCRs in parallel with a common gate terminal?

A. TRIAC.
B. Bilateral SCR.
C. Unijunction transistor.
D. Field effect transistor.

Answer 4

A. TRIAC.

Question 5

3-23C5: What are the three terminals of a TRIAC?

A. Emitter, base 1, and base 2.
B. Base, emitter, and collector.
C. Gate, source, and sink.
D. Gate, anode 1, and anode 2.

Answer 5

D. Gate, anode 1, and anode 2.

Question 6

3-23C6: What circuit might contain an SCR?

A. Filament circuit of a tube radio receiver.
B. A light-dimming circuit.
C. Shunt across a transformer primary.
D. Bypass capacitor circuit to ground.

Answer 6

B. A light-dimming circuit.