Relay flip-flop � Visual Art and Obscure Technology

Relay flip-flop � Visual Art and Obscure Technology

This circuit uses three relays. One input is the clock which is shown as a push switch. The other main input is the D or DATA input which is the two way switch on the left. When you apply power to the clock input, the circuit copies the state of the D input, either on or off, into the output relay called Q here. But the important part which is the tricky bit of the design is that the circuit is edge-triggered which means that following the moment that the clock input is energised, the D input can be changed without affecting the output. More specifically, the D input can come from the Q output of another flip-flop circuit with the same clock and there won’t be any race condition. This is because changes of state on the D input are guaranteed to be locked out before the Q relay changes to reflect the pre-existing state of the D input.