TDA2822 wireless headset circuit diagram

Many people have used TDA2822 to make audio-sensing wireless headphones , but found that they have not used TDA2822 properly! This chip is a two-channel audio amplifier, and many productions only use one channel and leave the other channel idle; or Make it into BTL form! Although the above method is feasible, it does not achieve the best effect in terms of application! The sound source of this type of headphone is a multi-turn magnetic core coil, and its frequency response characteristics are similar to the tape recorder head, so it should be in accordance with riaa (Recording Industry Association of America) ) equalization network for frequency correction to make the frequency response as flat as possible! The improved circuit is as shown below! The induction signal first enters one channel for amplification, and the output end passes through an attenuation network for frequency correction, and finally is fed into another channel through the potentiometer. Channel for power amplification! After this improvement, the listening sensitivity is firstly increased, which is helpful to cover up the background noise of the power amplifier; at the same time, the sound becomes soft and durable! This is very beneficial to language teaching in schools. Too high high frequency will cause The labial and dental sounds in the human voice are too obvious and affect the listening effect!

The author has installed multiple playback systems, and the brief introduction is as follows: 1. For the comprehensive installation of classrooms in schools, 50w broadcast amplifiers can be used, and single-strand copper (or aluminum) insulated wires with a cross-section of about 1 square millimeter can be used to make several large circles around the classroom. If the city teaching building is arranged in one circle on each floor, Just measure the DC resistance above 6ω! Note that both ends of the coil can only be connected to the 8ω output end of the amplifier! 2. Single classroom installation: Use thinner enameled wire to wind several times on the classroom ceiling, with a DC resistance of 4Ω or more! Then nail two binding posts on the side of the blackboard or install a socket! The teacher uses a radio with an output power of 5W or more as the sound source during class. Just connect the speaker output wire to the binding post! In this way, students listening with headphones will not interfere with other classes! It should be noted that adjacent classrooms or upper and lower floors cannot be used at the same time, otherwise crosstalk will interfere with each other! The school can adjust the class schedule appropriately solve!  

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