This circuit was found in February 1976, Radio Electronics magazine. The circuit is quite sophisticated using a fast-acting (thermometric) sensor and analog indicator.
This circuit was found in an ancient American documentation. The transformer is the type used in...
We found this circuit in a Poptronics of the 90s. The circuit operates from 100 kHz to 30 MHz and...
The circuit shown is from the SGS manual of linear integrated circuits of 1982. The L78xx is...