论文部分内容阅读
演示声音的波形,常用话筒作声电转换。市售动圈话筒不仅价格较高,而且输出电压很小,直接接到示波器上观察声波波形,往往是波形的峰一峰值太小,可见度很差。当声源过分靠近话筒时,又会使话筒产生明显的失真,影响教学效果。为此,笔者制作一只低成本(不到5元)的高灵敏话筒。电路如下图:R_c、R_b、C_1、C_2和三极管 BG 组成简单的共发射极交流电压放大器。用3时8Ω的扬声器进行声电转换。扬声器产生的音频电压经 C_1耦合到晶体管基极进行放大后,再经 C_2耦合输出。R_b 接到晶体管集电极,既
Demo voice waveform, commonly used microphone for sound and electricity conversion. Not only the high price of the market moving microphone, and the output voltage is small, directly connected to the oscilloscope to observe the waveform, the waveform is often the peak of a peak is too small, poor visibility. When the sound source is too close to the microphone, it will make the microphone produce obvious distortion and affect the teaching effect. To this end, I make a low-cost (less than 5 yuan) highly sensitive microphone. Circuit as shown below: R_c, R_b, C_1, C_2 and transistor BG composed of a simple common-emitter AC voltage amplifier. With 3 o'clock 8Ω speaker for sound and electricity conversion. The audio voltage generated by the speaker is coupled to the base of the transistor via C_1 for amplification and is then coupled via C_2. R_b connected to the transistor collector, both