This circuit is from a 1972 Motorola publication. The used transistor can still be found, but it can be used equivalent. The circuit is powered by the amplifier with which it must operate.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit using current components was found in an old documentation. It is a sequential circuit...
In the figure we have a signal detector using a tunnel diode. The circuit is from a Radio...