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本文介绍的对讲机结构简单易制,声音清晰宏亮,传输距离在千米以上,很适合小矿井生产和需要联络的场合作语言联络用。一、电路特点:集成电路TDA2003及其外围元件购成音量可调的功率放大器;转换按钮进行接听转换;扬声器既是放音喇叭又是传声话筒。机机或多机之间采用以功率输出作为信号传输,音量靠本机进行控制放大的方式,不因线路损耗而影响音量增益。本机还设有输出电平指示,以监视线路工作好坏。二、电路工作原理:TDA2003的①②脚为输出脚,③接地⑤为电源脚(接B+),④为输出脚(阻抗8Ω)。工作电源电压6～12V均可正常工作。转换开关S2平时位于“听”的位置,由对方输送来的功率信号长途跋涉已经较弱,经变压器T提高阻
This walkie-talkie introduced in this paper is simple and easy-to-structure structure, clear and loud voice, the transmission distance of more than kilometers, it is suitable for the production of small mines and the need to contact the field for language contact. First, the circuit features: Integrated circuit TDA2003 and its external components purchased volume adjustable power amplifier; conversion button to answer conversion; speaker is both playback speaker and microphone. The use of machine or multi-machine power output as a signal transmission, volume control by the local amplification method, not because of line loss and affect the volume gain. The machine also has an output level indicator to monitor the work of the circuit is good or bad. Second, the circuit works: TDA2003 ① ② feet for the output pin, ③ ground ⑤ for the power supply pin (then B +), ④ for the output pin (impedance 8Ω). Working power supply voltage 6 ~ 12V can work normally. Transfer switch S2 is usually located in the “listening” position, the power signal sent by the other party to travel long distances have been weak, the transformer T to improve the resistance