This is the receiver from the previous alarm system. The circuit is from Radio Electronics, April 1989, and has an LDR as the sensor. Optical devices should be used to improve performance.
This circuit had its assembly described in a Radio Electronics from March 1963. The circuit uses 2...
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...
We found this circuit in an English documentation from 1989. The integrated circuit used is not...