This 80's Exar circuit has a carrier detector for frequencies up to 500 kHz. The circuit uses a company 567 which is still a common component.
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...