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 was obtained in a 1984 publication, but it can be assembled using BC548 for TR1 and...
This circuit was found in an American documentation from 1969. The circuit memorizes when a...
This counter was found in the November 19983 issue of Radio Electronics magazine. The power supply...