We found this circuit in the July 1992 issue of Radio Electronics magazine. An optical system produces the light beam that, when interrupted, triggers the alarm. The sensitivity is adjusted by R4.
This circuit appears in other articles in this section, but it is very interesting. It is a...
This circuit works directly connected to the network and special care must be taken with its...
The oscillator indicated can produce signals from 50 kHz (approximately) to 7 MHz, depending only...