This circuit was suggested by Texas Instruments in a 1968 publication. The transistors are of the time, and modern equivalents can be used.
This configuration from the 1970s can be applied to modern equivalent operational amplifiers. The...
This interesting circuit was found in a 2006 publication. It is a timer that controls the engine...
This relay circuit with a dual channel MOSFET (not very common today) was found in an old American...