The sound principle of the electric piano is to use the keyboard as the on-off switch to form an electric pulse. Once the key is pressed, the internal crystal oscillator starts to work, forming a pulse to generate a certain frequency waveform, and then it is amplified by the frequency divider and sent to the speaker for sound. The whole sound production process depends on a simple frequency division analog circuit, so the keyboard has no force and string feeling, and the sound is relatively mechanical and monotonous.