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 was found in a 1962 publication. At the time there were high voltage batteries like the...
Suggested by Sprague in the 1980s documentation, this circuit can control three-phase AC motors....
This circuit divides the frequency of a 2 kHz signal by 2. The circuit was found in Philips...