Found in a 1964 CQ magazine this circuit consists of an automatic telegraphic key, providing the correct duration for points and dashes. The circuit can be made with a current PNP transistor.
This circuit was found in an 80's Electronic Engineering. The circuit uses operatives of the time...
The selected circuit was obtained in a Texas Instruments opto-electronics manual. The transistors can be...
In short wave receivers or in the recovery of signals from scratched discs this circuit can be...