Miniature wireless frequency modulated microphone circuit diagram

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. This circuit is an unlimited electronic production site. It has been used in an unlimited way to study. It can be in the corridor to lead to another. It has 20 meters away to realize our a group of fans's FM dreams. Now I am very missing. The days of practice, special dedication to everyone ... The circuit is as shown in the figure, the BG and L and triode junction capacitors constitute a high-frequency oscillation circuit triode is about 2 to 3p, to enable the frequency within the fm range, the coil should be in diameter. The 5MM core is wrapped around 7 laps, and the vibration when the capacitive microphone is tested, and the high frequency signal generation frequency is generated, and the frequency 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.

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