请教一个比较菜的问题，用一个IO来驱动一个喇叭，让它发出清脆的响声。

kanprin

请问其原理是什么？能否给个难民及的指点？
是否通过电流的变化，使喇叭发出不同的响声？
需要PWM控制？
没接触过，所以一片茫然。
谢谢。

yangsen

让你的端口输出一个1khz左右的方波就行了，端口驱动能力不够的话加个三极管

new007

响不响共鸣很重要,能大幅度提高声压级

kanprin

意思就是说改变频率来改变声音的高低？ 那如果直接加高电平，结果会如何呢 ？
当然，实践出真知，现在只是想从原理上先了解一下。

millwood0

you can think of a speaker as a combination of a small inductor and a resistor. so yes, if by changing the duty cycle of a pwm signal applied to a speaker, you can change the amplitude applied on the speaker - essentially how a class D amp works.

and if you use a l/c low-pass filter (assuming that your pwm output has low enough of an output impedance), you can actually get very good sound. the pwm frequency is typically at least 10 - 20x that of the highest frequency you want to output.