The circuit is from 1980s Linear Technology documentation. The components are of the time and circuit behavior curve is given along the diagram.
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...