Category Archive: Electronics

Dec 02


1. Draw a circuit diagram of OR gate.

2. What is a logic gate?

3. What types of charge-carriers are there in a n-type semi conductor?

4. Give the logical symbol of an AND gate. Mark the inputs and outputs.

5. Draw the logic symbol for a NAND gate.

6. Which biasing will make the resistance of p-n junction high?

7. Write the truth table for OR gate.

8. What is the change in the collector current, in a transistor of a.c. current gain 150, for a 100µA change in its base current?

9. When the voltage drop across a p-n junction diode is increased from 0.65V to 0.70V, the change in the diode current is 5mA. What is the dynamic resistance of the diode?

10. How does conductivity of a semiconductor change with rise in its temperature?

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Sep 10

Solution to HC Verma Problem

“Referring to HC Verma Part 2, chapter 29, Electric field and potential, Q 69 I think that Force is inversely proportional to square of the distance between the charged particles, so acceleration is not constant and hence v*v  =  u*u  + 2*a*s   is not valid in this case. [...]

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Feb 26

Transistor as a Switch

(This is one of the Expected Question for AISSCE Physics 2011)

Explain the action of transistor as a switch.

To answer this question (with proper understanding) you should have an idea of the three regions

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Aug 03

Law of mass action

When an intrinsic semiconductor is doped with pentavalent impurity, the number of free lectrons increases. Will it result in any change in the number of holes already present?

The answer is YES.


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Aug 03

The difference between electricity and electronics

Electricity is the branch of Physics (?) which deals with the flow of electrons and its effect. The electric bulb, electric iron etc are electric devices as they are based on the direct

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Aug 03


Doping is the deliberate addition of desirable impurities to an intrinsic semicounductor to modify its conducting propertires.

The impurity atoms added are called dopants and the semi conductor so formed

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