This circuit has the spark duration controlled by a 555 timer. The circuit was found in the 1990 special issue of Radio Electronics Experimenter magazine.
In the figure we show how to use an LM324 as a voltage comparator the reference voltage is...
This circuit was found in an old publication and operates in the 455 kHz IF band since the...
This circuit is from a Motorola manual from the 70s. The circuit can be implemented with more...