We found this circuit in a 1986 documentation. It uses only LEDs, batteries, resistors and the power supply which can consist of 4 batteries or a 9V battery. The basic circuit uses two-color LEDs.
This circuit triggers a remote doorbell when the phone rings. The circuit is for the 110 V mains...
This circuit was found in an ancient American documentation. With it is possible to double the...
This 555 IC circuit was found in the November 1994 issue of Radio Electronics magazine. The...