Found in the September 1972 issue of Radio Electronics magazine, this signal injector is based on the HEP580. The circuit is powered by two batteries and its frequency is basically given by C1.
Using an optocoupler this circuit turns on the light in a bedroom for a set amount of time when...
The presented circuit uses two old germanium transistors. We found this configuration in a...
The circuit shown fires an auxiliary flash from a flash commanded directly by the camera. The sensor...