Found in documentation from the 1980s, this circuit uses a SG1524. It is an uncommon integrated circuit nowadays. The circuit provides a current of 20 mA with a symmetrical voltage between 15 and 18 V.
Found in an issue of Elektor magazine in the 90s, this battery tester is based on the LM3914. The...
I found this circuit in a July 1982 English magazine. The circuit is still viable by simply using...
This circuit is from a 1966 Motorola Field Effect Transistors Manual. The circuit makes use of...