# When do I need to use an OR gate IC?

I'm currently designing a logic circuit to compare two 4-bit numbers using an XOR gate IC (TI CD4070B).

I'll then need to combine the output of these four XOR gates to into a single line using OR gates. If this combined feed returns a 1, then I'll know the numbers aren't equal.

My question is: do I need to use a dedicated OR gate IC, or can I simply wire together the outputs of the four XOR gates? My main concern is if one of the XOR gates returns a 1, then voltage will be back-fed into the outputs of the other three XOR gates (potentially damaging the chip or spreading back to the inputs of the XOR gate?).

• Your logic is correct. You could use a single 4 input or gate. – Sparky256 Sep 7 at 4:02