Wireless microphone circuit diagram composed of 9018 triode

The transmitting frequency is designed in the FM radio band, so it can be used with any FM radio to receive the high-frequency signal and restore the sound signal from the high-frequency signal to complete various purposes.

Wireless microphone uses:

1. Wireless microphone: Users can rotate and move 360 ​​degrees at will when singing, speaking or performing without any wires getting in the way.

2. Wireless broadcast: The teacher carries out live broadcast during the lecture, and countless students can use the radio to listen to the lecture, greatly increasing the number of people attending the lecture.

3. Wireless hawking device: When selling goods on the street, using a wireless microphone to hawk products has a certain novelty and will receive better advertising effects than ordinary microphones.

4. Wireless*: It has relatively good concealment and security. You can listen to it with radio headphones from a distance without worrying about the embarrassment of meeting on site.

5. Wireless alarm: Achieve unattended operation at a certain distance. For example, the door lock sound on the second floor and the first floor can act as a burglar alarm.

6. Wireless electronic doorbell: Since it can transmit sound wirelessly, it can also transmit doorbell sound wirelessly. When paired, it can also be converted into a wireless intercom.

7. Wireless electronic musical instruments: Use a radio to receive the sounds of musical instruments such as harmonica, erhu, and guitar, or use a power amplifier to amplify and broadcast them, so you can enjoy music better.

8. Electronic hearing aids: By adjusting the volume of the radio or microphone, amplifying the sound and then sending it to the earphones, the hearing of the elderly can be effectively improved.

9. Voice-controlled lantern: Change the speaker at the output end of the high-power amplifier to a 6V or 12V car light bulb with the same wattage, and adjust the volume and position.

10. Reading memory enhancer: Similar to a hearing aid, point the microphone at yourself and listen to the sound of your own reading to eliminate external interference and help focus.

11. Small radio station: It is suitable for schools, factories and other units to organize various programs by themselves. It can play music, news, notices, etc. and listen to it on the radio.

12. TV sound transponder: Using headphones to listen to TV while watching TV can not affect other people's sleep, but it is controlled by the length of the headphone cable. This device is not subject to this restriction.

Relevant production experience:

The closer distance between turns of the wireless microphone coil L1 and the replacement of a capacitor with a larger capacity will make the transmission frequency lower; to make the transmission frequency higher, the opposite measures need to be taken.

The variation range of the capacitance connected in parallel with L1 cannot be too large or too small, otherwise the transmission frequency will be outrageous, and a high-frequency transmission signal will not even be generated (the circuit will not oscillate).

If you want a longer transmission distance, please add better antennas to the radio and wireless microphone, and increase the power supply voltage of the wireless microphone appropriately.

L2 in the simple wireless microphone is short-circuited with an iron wire; L2 and L3 in the enhanced wireless microphone can be adjusted to maximize the distance.

Choose a high-end radio with higher sensitivity and greater selectivity for longer range reception.