RF Voltage from Power in a 50-Ohm System

Finned N-type RF dummy load on a laboratory bench with CentronRF watermark

For a purely resistive matched load, RMS voltage equals the square root of power in watts times resistance in ohms. State RMS and waveform assumptions.

How it works in practice

For a sinusoid, peak voltage is RMS voltage multiplied by the square root of two, and peak-to-peak is twice peak. Standing waves and modulation can increase maximum voltage. These calculations do not establish a component's insulation rating.

Example and interpretation

1 W in 50 ohms gives about 7.07 V RMS, 10 V peak and 20 V peak-to-peak for a sine wave.

Checks before use

  • Define load impedance
  • Calculate RMS voltage
  • Convert waveform peaks
  • Check actual voltage limits

Important limit

Do not use sine-wave peak conversion for an arbitrary waveform without checking its crest factor.

Related Centron RF product

SMA 2 W 6 GHz fixed attenuator. Use calculated levels to define a requirement, then compare it with the exact product’s current bandwidth, input power, impedance and available attenuation options. Calculations assume stated conditions and do not replace a component datasheet.

Further reading

Keysight: Fundamentals of RF and Microwave Power Measurements. This background reference explains general principles; the selected Centron RF model’s datasheet governs its own ratings.

Related guides

Educational guide. Numerical examples use the stated assumptions and are not test results for a supplied unit.