This circuit was found in the February 1980 issue of Radio Electronics magazine. The digital circuit was shown in two parts, using 20 LEDs in a configuration with the LM3914.
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...