This circuit with the ULN3784B appeared in the October 1984 issue of Radio Electronics magazine. It can typically be powered from 9 to 24 V.
This 1-transistor circuit for currents up to 50 mA was found in the August 1974 Radio Electronics...
This circuit is from 1997 when Camcorder-type video cameras that used powerful batteries were...
This is a commercial circuit for an AM radio with 4 transistors, published in a Japanese magazine in...