This circuit was found in a 1964 Electronic Design. The transistors are of the time, but can be employed as modern equivalents. The system is for car with contact breaker.
This configuration enables the use of low current switches or sensors to control high power loads...
Any JFET can be used in this circuit suggested by Electronics Now magazine, April 1993. The...
This ultra-low noise circuit was found in the May 1990 issue of Radio Electronics magazine. The...