Found in a 1968 Motorola manual, this DC circuit uses components from the era. The circuit fires in microsecond times. The Q3 transistor must be according to the controlled load.
Found in a European magazine from the 1980s, this circuit can amplify signals from 10 kHz up to...
This circuit indicates whether a cable or wire is energized by simply approaching its antenna. The...
Suggested by Intersil in documentation from the 90's, this circuit is valid for modern operating...