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.
Pulses in sequence 1 to 10 are produced by this circuit. The pulses can be used to drive output...
This calibrated circuit was found in documentation from the 1980s. It makes use of an integrated circuit...
This is a amplifier for XTAL high impedance earphones or piezoelectric types. Current drain is...