These circuits were designed on request. Both feature a flashing LED that, after a preset number of flashes will illuminate steadily until P...

This circuit generates an astonishingly real imitation of the chirping of the cricket. A suitable audio wave form is generated by IC2 and re...

This accurate one-pulse-per-second clock is made with a few common parts and driven from a 50 or 60 Hertz mains supply but with no direct co...

This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff.This ...

This timer was designed mainly to switch off a portable radio after some time: in this way, one can fall asleep on the sand or on a hammock,...

Short circuits or broken pcb tracks can be easily recognized by means of a Multimeter, but this tool can give wrong results when testing the...

A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. Parts: R1,R7________...