This simple circuit was found in a Japanese magazine in 1967. The circuit is listening on a headset and the coil is 50 + 50 turns of wire 28 or thinner on a ferrite rod.
Circuits similar to this appear elsewhere in this section. The transistors can be BC549 (low...
September 2017 - Vishay Siliconix SQ MOSFETs for automotive use are in stock for immediate...
In this circuit we show how to modulate the pulses produced by a 555 in frequency. The circuit can be...