The function of the 555 timer is mainly determined by two comparators. The output voltage of the them controls the state of the RS flip-flop and the discharge tube. It also contains 3 working states.

Compared to the simple diode needed to demodulate AM radio signals, the detector circuits used for FM are slightly more complicated. Wrapping your head around phase detectors, ratio detectors, ...

If you ever thought of experimenting with pulse-width modulation, this circuit should get you started nicely. We’ve kept simplicity in mind and used a dual 555 timer, making the circuit a piece of ...