This circuit was found in the April 1973 issue of Radio Electronics magazine. Using TTL technology, it was recommended for vehicles of the time. The circuit was connected to the contact breaker.
The oscillator in figure 1 can be used in alarm, call or warning systems, producing a sound of...
This circuit is from a 1973 documentation. In it we have the way of using a FET as an input of...
This circuit is for traditional old-style telephone lines found in an American 1980s...