This circuit operates with an AM radio tuned to or near 900 kHz if there is a station at this location. The coil consists of 60 + 40 turns 28 on a ferrite rod.
This circuit, found in an American publication from the 1970s, produces an audible tone in a...
This circuit was found in a 2006 publication. It can serve as the basis for a microcontrolled...
By adding a transistor to the output and some polarization features we can obtain a higher output...