BCD to Decimal Decoder and BCD to Seven Segment Display

BCD TO DECIMAL DECODER AND BCD TO SEVEN-SEGMENT DISPLAY

AIM:

To study the operation of seven segment display unit and decoder/driver IC7446/7447 and Verify the truth table of BCD to decimal decoder using gates.

MATERIALS AND TOOLS REQUIRED:

ICs 7446, 7490, 7420, 7400 LN542, resistors, IC trainer kit and Power supply.

THEORY:

BCD to decimal decoder: A decoder is a combination logic circuit that accepts an active level on its inputs representing a binary or BCD number and converts it to an output such as decimal or octal. The BCD to decimal decoder has four inputs corresponding to the BCD code and ten outputs each corresponding to a decimal digit.

BCD to seven segment decoder: This system needs an asynchronous decode counter 7490, a seven segment indicator LN 542 and a decoder/driver IC 7446. The seven segment indicator consists of seven LEDs labeled a through g. By forward biasing different LEDs we can display digits 0 to 9.

Circuit Diagram:

PROCEDURE:

            Check all the components and IC packages using multi meter and digital IC tester. Set up the circuits as shown in the figure.Verify the truth table of BCD to decimal decoder.  For the BCD  to seven  segment decoder, feed 1Hz  clock to the 7490 clock input and observe the output of the display.

RESULT:

BCD to decimal and BCD to seven segment decoders are set up.