Found in a 1980s German publication, this circuit tests batteries by type. The circuit is based on a range of LEDs of different colors and is given a table with indications for various voltage ranges.
Found in a 1966’s General Electric documentation, this circuit uses a triple diode from the time....
We found this circuit in the Linear Technology Applications of 1997. The circuit uses components of the...
This circuit was found in an old Hewlett Packard publication. Its purpose is to activate neon...