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.
This is a Japanese commercial circuit found in a 1967 documentation. The transistors are from the...
This circuit was found in a Radio Electronics from October 1952. The circuit equalizes the sounds...
This circuit is from an old American publication, but it can be easily implemented with modern...