4 components Make mini-wire frequency modulated microphones ----- fm Transmitter

It's too simple to see the picture above. The circuit has a very small element. Only 4, it constitutes a miniature wireless frequency band microphone, which is more stable, and the emission distance is greater than 10 meters. When the power is powered, the current is less than 0.5mA, so that the energy-saving microphone is still rare, 3V power is up to 30 meters. The circuit is shown that the BG and L and the triode junction capacitors constitute a high-frequency oscillation circuit triode of approximately 2 to 3p, to enable the frequency to fall within the FM, the coil should be around 7 laps in a diameter of 5mm, and the capacitive microphone is checked. The vibration is modulated with a high frequency signal generation frequency offset, and the frequency modulation is realized. Its emission distance is related to the size of the launch tube, and the resistance cannot be too large. It is not too small, between 300 ~ 500, and the power is less than 1 mW. When BG is selected, the FT of the tube must be greater than 300MHz, such as using a 2SC3358 high-frequency tube, the frequency is more stable, and the distance will be further. The inductance L is divided into two coils to wind, but the winding must be the same, and the L1 is 0.5 mm in diameter, and the lacquer line is wound around 4, L2 around 3 turns. The antenna can use 10 cm long soft wires, and the antenna will affect the frequency when used. It is very stable when it is fixed at a fixed location. This circuit can be loaded into the ink vial cover, and can also be installed in the pen holder, the battery uses a battery or a smaller number, but pays a switch when a small capacity battery is used.

Our other product:

Professional lightning protection system for Tower	Professional FM Radio Station Equipment Package	FMUSER FU-1000C 1000W FM Transmitter With USB Audio Input Interface
FMUSER 200W FM Radio Broadcasting Package	Hotel IPTV Solution	FMUSER FSN-1000T V5.0 1KW FM Radio Broadcast Transmitter