Found in 80's Electronic Engineering, this circuit can tune the frequency to be rejected. The power supply must be symmetrical.
With a unijunction transistor and a tunnel diode it is possible to obtain rise times of 1 ns with...
This circuit was found in old English documentation. It can be improved by using resistors of...
This circuit is from Delco Radio found in a 1968’s documentation. The transistors are of the time...