This circuit was found in the October 1989 issue of Radio Electronics magazine. It drives an auxiliary relay with the call signal for a possible louder bell.
This is one of the channels of an amplifier suggested by Westinghouse in 1970s documentation. The circuit...
This circuit works as both an injector and a signal follower. We found it in the May 1994 issue of...
This circuit is from Radio Electronics. The magazine no more exists, but the circuit can be...