This circuit was published in an article in Radio Electronics magazine in October 1988. It uses components that are still common today, except for the sensor, which is a special type from that time.
This circuit uses a 7812 and another regulator integrated circuit that is not very common...
The project is from a 1992 publication, but totally current by the components it uses. The LEDs...
We have a simple and useful circuit found in a 1982 documentation which generates a signal in the...