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.
We found this test circuit in a March 1967 Radio Electronics. The circuit uses a zener-regulated supply and...
This amplifier for small cassette tape players was found in an English documentation from 1969. The...
We found this circuit in a 2005 Linear Technology manual. The resistor is calculated for the...