Question

(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 1

(a) In order to convert alternating current into direct current, she can use full-wave rectifier. A full-wave rectifier uses two diodes, which enables it to pass both the positive and the negative side of the alternating current input. The diodes are connected to the transformer.

The full-wave rectifier requires that you use a center-tapped transformer. The diodes are connected to the two outer taps, and the center tap is used as a common ground for the rectified DC voltage. The full-wave rectifier converts both halves of the AC sine wave to positive-voltage direct current.

(b) The truth table and circuit symbol for NAND gate is shown below.