Sugar Cube fm transmitter circuit

Simple FM Transmitter Circuit Diagram - Sugar Cube

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The original simple and famous FM sugar cube transmitter circuit diagram that sold in the thousands back in the 70's. The tank circuit that determined the output transmit frequency consist of L1 and the 47 pF capacitor. The frequency was fixed and transmitted in the standard 88 to 108 MHz FM band. The choke in the emitter of Q1 was identified as a 43LQ105 that can still be purchased on the Internet. L1 was measured at 4 turns of # 22 copper wire 1/8" Air Wound. Q1 is a PN918 Transistor but most NPN RF Transistors should work in the circuit. I see no reason why the 47 pF capacitor can't be replaced with an adjustable of around 5 to 50 pf allowing adjustment for both the FM band and also into the VHF band. If the unit fails to oscillate in the VHF portion, simply replace the 20pF feedback capacitor from the emitter to the collector with a 5 to 10. Also this unit should work fine with a small 1.5V hearing aid batterey. I took the schematic of this simple to build fm transmitter circuit diagram and did all of the layouts for you including a full breadboarded circuit. Enjoy, John.

 

 

Simple FM Transmitter Circuit Diagram # 10 Stripboardsimple fm sugar cube transmitter circuit diagram, real viewsimple fm sugar cube transmitter circuit diagram, screen viewsimple fm transmitter circuit artworksimple fm transmitter circuit diagram, circuit board artworksimple fm transmitter circuit diagram, sugar cube
 

 


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Simple FM Transmitter Circuit diagram, sugar cube, Breadboard