This circuit was found in a 1964 Electronic Design. The transistor may be a current equivalent of general use. The frequency ranges from 100 to 150 Hz.
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...