Abstract: The basic function of the digital IC tester is to test digital IC for correct logical functioning as described in the truth table. It can test digital ICs having 14 pins. This model applies the necessary signals to the inputs of the IC, monitoring the outputs at each stage and comparing them with the outputs in the truth table. Any discrepancy in the functioning of the IC results in a fail indication through LEDs. The testing procedure is accomplished with the help of keys present on the main board. At this stage we had completed to test the most common used digital IC's used in our laboratories, mainly belonging to the 74TTL series. This tests various types of ICs like AND, OR, EX-OR, NAND, NOR and EX-NOR gates.

Keywords: Inequality detector, Multiplexer, Flip-flops, Socket and Counter.