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 traditional amplifier configuration is from the National Semiconductor's Linear Applications Handbook...
We found this circuit in a Radio Electronics from February 1966. The circuit uses a germanium...
This circuit originally appeared in a publication of 1997. With the changes, the circuit can be...