This circuit was found in the December 1982 Radio Electronics magazine. The components are of types that are still commonly found. The power supply is not included.
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
The integrated circuit used in this trigger is uncommon today. We found it in a documentation from...
This circuit is an alternative to the previous circuit. We found it in the same article in the...