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No.7, Yongxing 3rd Road, Chengdong Industrial Function Zone, Yueqing City, Zhejiang Province, China
The knob is not an invention that changes the world, but it can do things that the keys can't do.
As a mechanical construction, we don’t know which device used the knob first. Maybe a telegraph machine in the last century? Or a oscilloscope? It may also be a radio or a TV later, which is naturally born on electronic devices like many buttons, and then gradually became popular as a part of the audio equipment, and has been used as a controller ever since.