The transistor in this project found in the July 1994 issue of Electronics Now magazine can be any general-purpose type. The circuit is powered by the relay voltage up to 12 V.
This PA or Public Address amplifier with a few watts of power was found in the March 1986 Radio...
This circuit is from a Popular Electronics from the 90s. The circuit has a tone frequency...
This circuit is a telephone line simulator and can be used for internal communications. It is...