This circuit was found in the April 1970 Radio Electronics magazine. The dual function circuit uses 4 transistors and is connected to the vehicle's contact breaker.
In the figure we have a piezoelectric transducer drive circuit that can be used in conjunction with the...
This circuit is from a Ferranti publication of 1968. The circuit generates a signal according to the...
This is one of the possible triac power control configurations using as a trigger element a...