Power Electronics MCQs Part 4

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Power Electronics MCQs Part 4

The Thyristor (SCR) is a

The Thyristor (SCR) is a

  1. P-N-P device
  2. N-P-N device
  3. P-N-P-N device
  4. 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

  1. Three terminal, bipolar, current controlled device
  2. Three terminal, unipolar, voltage controlled device
  3. Two terminal, bipolar, voltage controlled device
  4. 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:

  1. Alpha
  2. Beta
  3. Gamma
  4. 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:

  1. Rectifier
  2. Inverter
  3. Chopper
  4. 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

  1. Ic increases
  2. Ic decreases
  3. Ic remains constant
  4. None of these

Correct Answer: 1. Ic increases

Continue Reading: Power Electronics MCQs

Also See Electrical Engineering MCQs here

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