The simplest frequency modulation microphone production

The simplest frequency frequency microphone circuit is as shown in the figure, it is too simple. 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. . BG and L and triode junction capacitors constitute a high-frequency oscillation circuit triode to have an approximately 2 to 3p, such that the frequency is in the range of the FM, and the coil should be in the diameter of 5 mm, and the vibration modulation when the capacitive microphone is tested. High frequency signal generation frequency offset, and realizes frequency modulation. 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 2SC3357 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. When you make a fan, please choose the triode because the BC junction of each triode is different, and the wireless microphone transmit frequency is in a large frequency range according to the picture, and the spacing of the coil should be mobilized at any time. Or in a small capacitance of the BC combined with 5-15p, the effect is better, it is easier to adjust. If your parameters are selected, this microphone can work properly. This circuit can be loaded into the small bottle cap, and can also be mounted in a pen cover, battery A13 battery or smaller, but pay attention to a small capacity battery.

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