This Motorola circuit is from 1965. Collector currents must be 7 and 12 A for transistors. Equivalents may be used. The circuit is for contact breaker cars.
This simple intercom for home use was found in a 1979 publication. It can be easily mounted with...
This circuit was obtained from American documentation from the 1990s. The transformer can be a car...
This wired intercom circuit was found in an English publication from the 80's. The integrated...