Two transistors on a regenerative switch are used to trigger a triac. This circuit is from the RCA Power Circuits manual. Transistors admit equivalents.
This circuit is from an 80's Radio Electronics. The circuit has several output options for 50 mA...
The absence of a pulse in the pulse train applied to the input of this circuit causes a high level...
This is one of the many anti-deboucer circuits the reader can find on this site. The base is TTL...