Using the 723 integrated circuit, this circuit was found in an article on power supplies in the August 1971 Radio Electronics magazine. The transistor may be the BD136 on a heatsink.
We have several circuits like this on the website. What it does is generate a signal in the range...
Found in American documentation from 1968 this circuit is based on discrete components in addition...
By connecting several photocells in series, we can directly activate a sensitive relay, as shown in...