# What is the simplest analog circuit for integer addition modular 2?

This probably is a rudimentary question. I would like to have a simple analog (switch) circuit for addition modular 2, or $a_1+a_2+\cdots +a_n$ (mod 2). Certainly, digital transistors can accomplish this, but I would prefer analog devices if the circuit is simpler. In practical terms, I would like to design a switch circuit to control a light, where fixing all other switches, any one of them can switch the light on and off. For $n=2$ or 2 switches, someone earlier has already suggested using two back to back single-pole-double-throw switches.

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May not be the simplest, but implementing n input xor gate using transistors is a solution. –  nidhin Jul 12 at 14:52
@nidhin, yes, but I would prefer simpler analog circuit. –  Hans Jul 12 at 15:34