Here are some DIY FM Transmitter circuits that we have been published on electroschematics.com. This do-it-yourself fm transmitters are pretty easy to build and will give you a good feeling when you’ll hear the music on the radio receiver.
Don’t forget to write your comments and post some links if you know good designs that are not in the best of list.
Best of Do-it-yourself FM Transmitters
This FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor BF200 (T2), a driver built around transistor 2N2219 (T3) and a power amplifier built around transistor 2N3866 (T4).
Maxim now has available a series of five integrated oscillator building blocks in the MAX260x series which cover the frequency range between 45 and 650 MHz. The MAX2606 covers the VHF band, although the frequency can only be varied by approximately ±3 MHz around the midrange frequency set by the coil L.
Let’s construct a low-power FM transmitter using surface-mount devices (SMD) that will be received with a standard FM radio. Soldering surface mounted devices is not so hard and actually is quite easy. The figure below shows the schematic of the transmitter which consists of two stages: an oscillator and an output amplifier. Modulation is from an electret microphone but you can use a low power audio source.
Take a look at this fm spy transmitter which can be used as a bug transmitter or as fm bug too. It uses a single IC 74F13, one coil, a capacitor, one trimmer, one resistor and ofcourse one electret mic. This spy bug is so easy to build and can give you a total coverage range of about 3 to 5 meters. You may want to use a small 100mW amplifier to give a little extend transmission range so you can spy from other location.
A simple USB FM transmitter that could be used to play audio files from an MP3 player or computer on a standard VHF FM radio by connecting it to an USB port. The circuit use no coils that have to be wound. This USB transmitter can be used to listen to your own music throughout your home.
This is very stable, harmonic free, long range fm transmitter circuit which can be used for fm frequencies between 88 and 108 MHz. It has a very stable oscillator because you use LM7809 stabilizer which is a 9V stabilized power supply for T1 transistor and for frequency adjustment that can be achieved by using the 10K linear potentiometer. The output power of this long range rf transmitter is around 1W but can be higher if you use transistors like KT920A, BLX65, BLY81, 2N3553, 2SC1970, 2SC1971.
A very good 1 watt fm transmitter circuit, very easy to build circuit. It has 4 transistors, one is a very stable oscillator, followed by a buffer stage to prevent frequency variation when you adjust the transmitter. Next is a resonance stage and the final stage built with a minimum 1W transistor which must have a heatsink.
This low power transmitter is designed to use an input from another sound source and transmits on the commercial FM band. This low power fm radio transmitter it is actually quite powerful…
BA1404 is a IC designed for fm mini stereo transmitters. It can be used as a pc fm transmitter, ipod fm transmitter, mp3 transmitter or even car fm transmitter because it has a small pcb dimension ( can fit anyplace ) and maximum 3V power supply.
What do you think about this diy fm transmitters? Will you try any of it? Have you ever build one? Share your experience in the “Comments section” after this article.