The principle of his "invention" is that when the water level reaches the two metal strips the water closes the electric circuit, thus the buzzer sounds to warn the user that the cup is full.
这项发明的原理是当水位线升高至两条金属线之间的时候，水阻断电路。蜂鸣器则警示水杯已呈满水。
The principle of his "invention" is that when the water level reaches the two metal strips the water closes the electric circuit, thus the buzzer sounds to warn the user that the cup is full.
这项发明的原理是当水位线升高至两条金属线之间的时候，水阻断电路。蜂鸣器则警示水杯已呈满水。
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