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.
This circuit is from a 1966 Motorola Field Effect Transistors Manual. The circuit makes use of...
This circuit was found in an American documentation from the 90's. The transistor is a general...
In the figure we have a high input impedance stage with a general purpose PNP transistor. An NPN transistor...