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.
We found this conventional astable circuit in Ferranti's 1974 transistor manual. Transistors are...
With the circuit shown it is possible to measure very low resistances, of the order of fraction of ohm,...
In the figure we show how to use a common transformer by changing its secondary to obtain a...