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 found in Motorola's 1968 documentation. It can be built on current equivalent...
This simple charger was found in a 1980s documentation. The transistor may be the TIP42 with a...
This article is from the Italian magazine Sperimentare number 11 of 1975. It can be assembled with...