Many times we want to make fm transmitter which is simple to build and has a good range. So here is a simple fm transmitter circuit which contains only few components and also has long range. C3 is a 1 - 40 pf trimmer capacitor and L1 is 8 to 10 turns of hookup wire of 22 guage
wound on 6mm form. The size of a standard pencil is also 6mm so you can use a round pencil as form to wind the coil. The optional resistor shown in figure 2 is to limit the voice sensitivity for example a 10K resistor will resist the voice signal coming from microphone more as compare to the 1K resistor. If you want sensitive microphone do not use optional resistor. For Antenna use a piece of 12 inch hookup wire. Set a blank spot on a fm radio and slightly adjust the trimmer capacitor with any non conductive tool to tune the transmitter.