Hi all,

I am not the digital expert, so I had to look at my “TTL Introduction Manual” (idea: Max Guerth, ~ 1971).

The “normal” [E]XOR truth table looks like this:

The above circuit with the relay and three (!) switches is rather confusing to me, because there are 3 x 2 states. That are – from my point of view – this combinations, where the A and B inputs are not really clear to me – sorry…

The switches are numbered from left to right. Maybe you have an explanation which I may understand 😉



  • This reply was modified 2 years, 3 months ago by Michael. Reason: Changed font and size styling for easier reading