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.
The digital target shot shown in the figures (weapon and target) was found in a 1992 documentation but can...
This amplified speaker is from a Radio Electronics from September 1988. The power integrated...
The transistors used in this 1985 Radio Electronics circuit are for general use. The gain pot can...