Power Electronics MCQs Part 4
Contents
The Thyristor (SCR) is a
The Thyristor (SCR) is a
- P-N-P device
- N-P-N device
- P-N-P-N device
- None of these
Correct Answer: 3. P-N-P-N device
Explanation: A Silicon-Controlled Rectifier, or SCR, is essentially a Shockley diode with an extra terminal added. This extra terminal is called the gate, and it is used to trigger the device into conduction (latch it) by the application of a small voltage. The figure below displays physical diagram and schematic symbol of SCR.
Read more about SCR in this article
A power transistor is a
A power transistor is a
- Three terminal, bipolar, current controlled device
- Three terminal, unipolar, voltage controlled device
- Two terminal, bipolar, voltage controlled device
- Two terminal, unipolar, current controlled device
Correct Answer: 1. Three terminal, bipolar, current controlled device
The ratio of collector current to base current in a transistor is known as
The ratio of collector current to base current in a transistor is known as:
- Alpha
- Beta
- Gamma
- Zeta
Correct answer: 2. Beta
Explanation:
The ratio of collector current to base current, β is the fundamental parameter characterizing the amplifying ability of a bipolar transistor. β is usually assumed to be a constant figure in circuit calculations, but unfortunately this is far from true in practice. As such, manufacturers provide a set of β (or “hfe”) figures for a given transistor over a wide range of operating conditions, usually in the form of maximum/minimum/typical ratings. It may surprise you to see just how widely β can be expected to vary within normal operating limits. One popular small-signal transistor, the 2N3903, is advertised as having a β ranging from 15 to 150 depending on the amount of collector current. Generally, β is highest for medium collector currents, decreasing for very low and very high collector currents. hfe is small signal AC gain; hFE is large AC signal gain or DC gain. Continue Reading at: Top 10 Transistor ratings
The device which performs AC to DC conversion is known as
The device which performs AC to DC conversion is known as:
- Rectifier
- Inverter
- Chopper
- Cycloconverter
Correct answer: 1. Rectifier
Also See MCQs on SCR here
For a power transistor, if the base current IB is increased keeping VCE constant, then
For a power transistor, if the base current IB is increased keeping VCE constant, then
- Ic increases
- Ic decreases
- Ic remains constant
- None of these
Correct Answer: 1. Ic increases
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Also See Electrical Engineering MCQs here