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.
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:
Rate this question :






















(i) Explain with the help of a diagram the formation of depletion region and barrier potential in a pn junction.
(ii) Draw the circuit diagram of a half wave rectifier and explain its working.
Physics - Board PapersWrite the two processes that take place in the formation of a p-n junction. Explain with the help of a diagram, the formation of depletion region and barrier potential in a p-n junction.
Physics - Board PapersName the junction diode whose I-V characteristics are drawn below:
Using a suitable combination from a NOR, an OR and a NOT gate, draw circuits to obtain the truth tables given below:
(i)

(ii)

Physics - Exemplar