This small switched regulator was found in an 60’s Optical Electronics. The circuit uses an integrated from the time, which is difficult to obtain today.
These circuits from a May 1994 Electronics Now take advantage of the noise from the junctions of...
We found this amplifier for automotive use in the Philips integrated circuit manual from 1990. The...
This very simple circuit uses a phototransistor and a very sensitive relay (reed type) being used...