FM Transmitter

FM Transmitter

A portable FM transmitter that can be used to replace a FM microphone.Notes:From the notes I made experimentally, C3 is vital to the circuit and without it the circuit may become unstable. C4 is in parallel with C5 and presents a moderate load impedance. Finally all transistors are NPN. The circuit works well and has proved reliable.L1 Details:

                       Where L1 = inductance in uHr = radius of coil in inchesl = length of coil in millimetres (mm)n = number of turns on coil

Using the above values, the inductance of L1 can be calculated. A diameter of 5.5mm = 0.22 inches, the radius is half this value or 0.11 inch, the length is 4.5mm and number of turns, n = 6. This gives L1 a value of: