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 amplifier can be used for public-address or other applications. Three transistors of the time...
This circuit was found in a 1967 Electronics World. The circuit uses components of the time that...
This circuit was obtained in a June 1987 magazine Hands-On. It is a circuit that indicates on an...