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.
The buffered phase shift oscillator circuit shown in the figure oscillates at a frequency of 2.9...
This circuit came out in a Popular Electronics from December 1995. It is a double T configuration that...
This circuit is from documentation from Analog Devices from the 90s. The circuit uses operational...