This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
This circuit is from an old documentation. Integrated circuit 723 is not common today. The power...
This circuit uses a diode as a radiation sensor. The operational ones are old because the...
This good gain antenna up to 30 MHz was found in an American 1990s documentation. The circuit can be...