This circuit was found in an Electronic Design. It makes use of a relaxation oscillator to trigger an SCR and two relays. The circuit operates at frequencies of 12 to 180 cycles per minute.
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
A negative pulse applied to the input of the circuit shown in figure bellow turns on the relay....