This circuit was found in a 1968 Hughes documentation. The transistors are from that time. The coil is for the medium or short-wave range.
In the figure we show our first circuit that consists of a simple touch switch capable of driving a...
This circuit was found in an 80's Electronic Engineering. The power supply must be symmetrical. The...
This metal detector was found in a French magazine Radio Plans from 1977. The phone can be a...