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.
This indicator circuit used and game machines (arcades) to indicate that the machine is being...
If the reader still uses silk screen printing tables this is an interesting circuit found in a 1994...
This amplifying step was found in an old American publication. The transistor is made of germanium and...