MCQ
2521. In an SCR circuit, the angle of conduction can be changed by-
Changing anode voltage.
Changing gate voltage.
Reverse biasing the gate.
None of the above
2522. If firing angle is increased, then the output of an SCR-
Remains the same
Is increased
Is decreased
None of the above
2523. A voltage divider consists of two 100k resistors and a 12V source. What will the output voltage be if a load resistor of 1 MQ is connected to the output?
0.57V
12V
5.7 V
6 V
2524. The parallel combination of a 470 Ω resistor and a 680 Ω resistor is in series resistors with the parallel combination of four 2k Ω The total resistance is-
1.650 Ω
1.0782 Ω
77.8Ω
778 Ω
2525. If the ac supply is 50Hz, what will be the ripple frequency out of the full wave rectifier?
50Hz
100Hz
60Hz
20Hz
2526. An SCR is a solid state equivalent of-
Triode
Gas-filled triode
Pentode
Tetrod
2527. When SCR starts conducting, which loses all control?
Cathode
Anode
Gate
None of the above
2528. An SCR has three terminals viz-
anode, cathode, grid
cathode, anode, gate
anode, cathode, drain
none of the above
2529. If the temperature of the diode increases, then leakage current-
Remains same
Increases
Decreases
Becomes zero
2530. An SCR behaves as a—switch.
Unidirectional
Mechanical
Bidirectional
None
2531. Approximately how many milliamperes of current flow through circuit with a 40V source and 6.8 ΚΩ of resistance?
27.2 mA
5.9 mA
59 mA
590 mA
2532. If gate current is increased, then anode-cathode voltage at which SCR turns ON-
is decreased
remains the same
is increased
none of the above
2533. An SCR is a --triggered device.
Voltage
current
Voltage as well as current
None of the above
2534. An SCR has PN junctions.
Two
Four
Three
None of the above
2535. AC power in a load can be controlled by connecting-
Two SCRs in series
Two SCRs in parallel
Two SCRs in parallel opposition
None of the above
2536. An SCR is made of silicon and not germanium because silicon-
is inexpensive
is mechanically strong
has small leakage current
is tetravalent
2537. An SCR has-semiconductor layers.
Two
Three
Four
None of the above
2538. An SCR is turned off when-
Anode current is reduced to zero.
Gate voltage is reduced to zero.
Gate is reverse biased.
None of the above.
2539. In an SCR circuit, the generally --that of breakover voltage.
Equal to
Greater than
Less than
None of the above
2540. What is the approximate resistance setting of a rheostat in which 650 mA of current flows with a 150V source?
9.7 Ω
97 Ω
23 Ω
230 Ω