Suggested by a 90’s Radio Electronics, this circuit automatically activates the recording switch of an old tape recorder. It can be adapted for other purposes.
Found in Philips documentation from 1968 this circuit operates at frequencies up to 10 MHz with 76...
This circuit was found in a European technical documentation from 1991. It is a circuit that must...
This harmonic oscillator controlled by crystal was found in an American documentation of the 90's....