Goal

To create a bench-top digital circuit that can be used to test the 14 pin 74xx series chips.

Working

The user needs to place the test IC in the circuit and provide all the input combinations as per the truth table of the IC. The outputs of the test IC are compared with that of a working IC of the same kind. All the gates on the IC are tested for all the input combinations. If the outputs of all the gates for a certain input combination is correct a designated LED lights up in the circuit(As seen in Video 1). When the outputs for all the input combinations are correct the result LED(top-left corner in the Video 1) lights up indicating a correctly functioning IC.

My Role

I was responsible in designing and assembling the circuit.

Challenges

As the IC's had to be tested for all the input combinations the circuit had to remember the output of the previous input combinations. For this a shift register was used to load the all the outputs to a compartor which would test the correctness of the outputs.