This circuit from the 90s, found in an Electronic Engineering can be used as a shield since its control is digital with TTL logic of 5 V. The components used are still common today.
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...