I've never built a circuit like that, I mostly use it for hidden doors and passages and sometimes controlled lighting.
Here, let me show you something cool then.
This right here is a basic toggleable and configurable infinitely repeating circuit that I slapped together really quickly.
You see, when the lever is switched down and the piston goes up, it completes the circuit and allows the energy to flow continuously.
In terms of redstone circuit designs, this basic one by itself is actually pretty darn useful and versatile.
