This sensitive three-transistor circuit was found in Electronics Now magazine and is earphone-readable. The tuned range depends on the coil.
LEDIL provides through Mouser Electronics a series of lenses for use in greenhouse horticulture....
Any FET can be used on this 80's circuit. Power can be supplied with batteries. The output is...
This circuit was obtained from an 80s factory manual. The integrated circuits used are uncommon...