The maximum value of sine wave voltage is divided by root number 2, and the result is the effective value of sine wave voltage. Expressed by the formula: U = up/root sign 2 equals 0.707Um.
Sine wave is a signal with a single frequency component, so it is named because its waveform is sinusoidal in mathematics. Any complex signal, such as spectrum signal, can be regarded as a composite of many sine waves with different frequencies and sizes.