Q. 204.0( 4 Votes )

(a) A student wants to use two p-n junction diodes to convert alternating current into direct current. Draw the labelled circuit diagram she would use and explain how it works.

(b) Give the truth table and circuit symbol for NAND gate.

Class 12th Physics - Board Papers All India & Delhi - 2018

Answer :

a) To convert alternating current into direct current, we need a full wave rectifier. The circuit diagram for a full wave rectifier is given below:

The working of this circuit is as follows:

i) During one half cycle (of the input ac) diode D1 alone gets forward biased and conducts. During the other half cycle, it is diode D2 (alone) that conducts.

ii) Because of the use of the centre tapped transformer the current though the load flows in the same direction in both the half cycles.

Hence we get a unidirectional/ direct current through the load, when the input is alternating current.

b) The circuit symbol and truth table for NAND gate is given below:

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(a) A student wants to use two p-n junction diodes to convert alternating current into direct current. Draw the labelled circuit diagram she would use and explain how it works.

(b) Give the truth table and circuit symbol for NAND gate.

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