VCR timer or other recorder timer is properly programed to turn ON active channel for week, month, whatever it can be programmed as record time. Make sure VCR is not on video pass through mode. If VHS tape is in player it may turn OFF when tape ends.
Left side of circuit is plugged into VCR Output. AC 1 kHz. generator and 1 uf capacitor is added to simulate when VCR timer turns on output signal. Close left switch to see current build up and close right side relay. This will take several seconds. When VCR Output stops it takes several seconds before closed relay OPENS.
Parts are three 2N2222 transistors, three 1N4148 diodes. Adjust circuit values for your relay and test set up to make sure video output signal will trigger relay switch.
