Found in American documentation from the 1980s, this circuit makes use of components of the time, which are uncommon today. The circuit detects the approach using a sensor formed by metal plates.
Found in an Electronics Now from the 90s, this application uses an integrated circuit from the...
This circuit can be applied to other 3-terminal regulators and equivalent transistors can be used....
This circuit was found in an old Electronic Design used to apply digital signals to an analog...