Play dough circuits 2: experiment with electricity Last time, we went through the basics of how to make simple electrical circuits with play dough and light-emitting diodes, now it's time to ...

Also, the known J-and D flip-flops first needed to use an anti-glitch R-S circuit, making the design too complex. So, I tried a simple circuit using a 7402 quadruple NOR gate (see the figure).

I needed a simple LED indicator showing that a particular voltage level had been reached—specifically, that a capacitor had charged to a particular potential. I was convinced that there must be ...