mini fm transmitter circuit

Posted on Feb 6, 2014

This ambit is a simple two transistor (2N2222) mini FM transmitter. No authorization is appropriate for this transmitter according to FCC regulations apropos wireless microphones. If powered by a 9 volt array and acclimated with an antenna no best than 12 inches, the mini fm transmitter will be aural the FCC limits. The microphone is amplified by

mini fm transmitter circuit
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Q1. Q2, C5, and L1 anatomy an oscillator that operates in the 80 to 130 MHz range. The oscillator is voltage controlled, so it is articulate by the audio arresting that is activated to the abject of Q2. R6 banned the ascribe to the RF section, and it`s amount can be adapted as all-important to absolute the aggregate of the input. L1 and C6 can be fabricated with wire and a pencil. The inductor (L1) is fabricated by ambagious two pieces of 24 barometer cloistral wire, laid ancillary by side, about a pencil six times. Remove the braid you accept formed and alleviate the two coils afar from anniversary other. One of these coils (the bigger attractive of the two) will be acclimated in the catchbasin circuit, and the added can be acclimated in the abutting one you build. The antenna for mini fm transmitter (24 gauge wire) should be soldered to the coil you made, about 2 turns up from the bottom, on the transistor side, and should be 8-12 inches long. To make C6, take a 4 inch piece of 24 gauge insulated wire, bend it over double and, beginning 1/2 ³ from the open end, twist the wire as if you were forming a rope. When you have about 1 ³ of twisted wire, stop and cut the looped end off, leaving about 1/2 ³ of twisted wire (this forms the capacitor) and 1/2 ³ of untwisted wire for leads.

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