Ziddik
Member
Here is a very simple,working and tested Fm transmitter circuit for newbies! It has built and tested by me and works a very long time using a 3.7 volt mobilephone battery! You may expect about 100-150 meters with a 400cm long antenna! Try more length for cover more range, the inductor can be an 8 turn,3.5 diameter of copper wire eg. Take a pen refill and wound 8 turns on it,remove the coil and solder it on the circuit, the second inductor that connected directly to the antenna is not needed plus adding a 22n (223) ceramic capacitor to couple the antenna will be useful to get rid of those frequency changing problem when touch or move towards the antenna, (i used the copper wires from a damaged transformer to make coils and it works fine) and i used 2xBC547 transistors,.. This is just a very basic fm tranmitter for newbies to work with..Good luck