This circuit was found in Philips documentation from 1967. The components are of the time, being transistors like BCY38 for TR1, BC108 for TR3, and others depending on currents.
This circuit can be implemented with other operational amplifiers. The formulas for calculating the...
This circuit is from a 1953 publication, consisting of an AM radio with 3 germanium transistors that,...
The sensor of this circuit is a common silicon diode and it directly drives a small cooler with a...