According to the sources, the relationship between the root mean square (rms) voltage ($V$) and the peak voltage ($v_m$) is defined by the equation $V = \frac{v_m}{\sqrt{2}}$ . By rearranging this formula, we find that the peak voltage is equal to $\sqrt{2}$ times the rms value ($v_m = \sqrt{2} V$) . For instance, a household line voltage of 220 V (which is an rms value) has a peak voltage of approximately 311 V ($220 \text{ V} \times \sqrt{2}$) .