To Study the Characteristics of a Common Emitter NPN (or PNP) Transistor and to Find Out the Values of Current and Voltage Gains - Physics Practical Class 12 Viva Questions with Answers

  1. What is a transistor?

Answer: A transistor is a three-terminal semiconductor device which is mainly used to amplify or change the direction of electronic signals.

  1. Who invented the transistor?

Answer: Walter Brattain, John Bardeen, and William Shockley invented the transistor.

  1. Where are transistors used?

Answer: Transistors are used in oscillators, amplifiers, and switches.

  1. What are the two types of transistors?

Answer: The two types of transistors are

  1. Bipolar Junction Transistors (BJT)
  2. Field Effect Transistors (FET)
  1. Define bipolar junction transistors.

Answer: A bipolar junction transistor is a semiconductor three-terminal device which features two P-N junctions and is able to amplify or magnify electrical signals.

  1. What are the three terminals seen in the Field Emitter Transistor (FET)?

Answer: Three terminals of Field Effect Transistors (FET) are the source, gate, and drain.

  1. What is an NPN transistor?

Answer: NPN transistor is a type of transistor in which a p-type semiconductor is sandwiched between two p-type semiconductors. In NPN transistors, electrons are the majority charge carriers, and holes are the minority charge carriers.

  1. What is a PNP transistor?

Answer: PNP transistor is a bipolar junction transistor formed with three layers of semiconductor material, with two P-type regions and one N-type region.

  1. Define input resistance.

Answer: Input resistance is the small resistance provided by the collector junction of the transistor because of forward biasing.

  1. Define output resistance.

Answer: The output resistance is the high-value resistance provided by the collector junction because of reverse biasing.

  1. What are the three terminals of the transistor?

Answer: Emitter, base and collector are the three terminals of the transistor.

  1. What is the formula to calculate the current gain?

Answer: The formula to calculate the current gain is:

\(\begin{array}{l}\beta =\frac{\Delta I_{c}}{\Delta I_{b}}\end{array} \)
  1. What are the different sections of the semiconductor junction transistor?

Answer: The emitter, base, and collector are the different sections of the semiconductor junction transistor.

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