Rms voltage

Definition

RMS (Root Mean Square) voltage is the effective value of an alternating current (AC) voltage, which represents the amount of work that the voltage can perform. It is calculated as the square root of the average of the squares of all instantaneous values in a cycle.

5 Must Know Facts For Your Next Test

1. RMS voltage is essential for comparing AC and DC voltages because it provides a measure of AC power equivalent to DC power.
2. The RMS value is approximately 0.707 times the peak value for a sinusoidal waveform.
3. In mathematical terms, $V_{\text{rms}} = \frac{V_{\text{peak}}}{\sqrt{2}}$ for a pure sine wave.
4. RMS voltage is used in calculating power dissipation in resistive loads using the formula $P = V_{\text{rms}}^2 / R$.
5. Measurement tools like multimeters often display RMS values for AC measurements.

Review Questions

• How do you calculate RMS voltage from peak voltage for a sinusoidal waveform?
• Why is RMS voltage used instead of peak or average voltage when measuring AC power?
• What is the relationship between RMS and peak values in a sinusoidal AC circuit?

Related terms

Peak Voltage: The maximum instantaneous value of an alternating current (AC) waveform.

Average Voltage: The arithmetic mean of all instantaneous voltages over one complete cycle of an AC waveform.

$V_{\text{rms}}$: $V_{\text{rms}}$ (Root Mean Square Voltage) represents the effective value of an AC voltage and is used to calculate power in AC circuits.