PWM Duty Cycle Calculator
Calculate PWM duty cycle and average voltage. Enter circuit values to calculate the selected electrical quantity.
PWM Signal
Electronics guide · Signals, timing, and radio frequency
About PWM Duty Cycle Calculator
Estimate the average output voltage for a pulse-width-modulated signal from its high voltage and duty-cycle percentage. It assumes the signal switches between the entered high level and zero volts.
Signal and RF calculations connect frequency, period, wavelength, bandwidth, sampling, impedance, and ratios. Results often assume ideal propagation or a simplified signal model; real cables, antennas, clocks, and converters can add losses, tolerances, reflections, and environmental effects.
How to Use This Tool
- 1.Enter the signal's high voltage in volts.
- 2.Enter duty cycle as a percentage from 0 to 100.
- 3.Calculate and review the average voltage along with the input values. Consider the load and waveform before treating this as a DC output.
Technical Details to Check
1.Frequency and time are linked
For a periodic signal, period is the reciprocal of frequency. Convert prefixes carefully: hertz, kilohertz, megahertz, and gigahertz differ by powers of one thousand.
2.Propagation depends on the medium
Wavelength is related to frequency and propagation speed. A free-space estimate differs from wavelength in a cable or material where the signal travels more slowly.
3.Logarithmic ratios need a reference
Decibels and related units describe ratios, often with a stated reference such as dBm. Check whether the tool is converting power, voltage, or a normalized ratio before using the value.
4.Sampling is not reconstruction quality
A sampling condition can help assess whether a signal's frequency content is representable, but real filters, clock jitter, noise, and system bandwidth also affect sampled data.
How the Calculation Works
For a two-level waveform between Vhigh and 0 V, average voltage = Vhigh × duty cycle/100. The duty cycle is the fraction of each period spent at the high level. This arithmetic average does not include switching frequency or ripple filtering.
Worked Example
A 5 V pulse at 40% duty cycle has an ideal average of 2 V across a complete period, assuming a 0 V low state.
Where This Tool Can Help
Understand PWM average level, compare duty settings, and estimate the input to a simple low-pass or load model.
Converting signal units
Move between frequency, time, wavelength, or power representations while keeping the source unit and reference clear.
Checking a communications setup
Estimate baud timing, clock tolerance, or signal ratios, then compare the result with the transceiver and protocol requirements.
Planning an RF or antenna estimate
Use a frequency-based result as a starting point and account separately for material, antenna geometry, matching, and the surrounding environment.
Reviewing sampled signals
Check a theoretical sampling relationship before testing the actual signal path, filters, converter limits, and clock quality.
Tips for More Reliable Results
- Write down the frequency, time, impedance, and reference units before entering a value.
- Check whether the formula assumes free-space propagation, ideal components, or a matched load.
- For dB values, identify the reference and whether the underlying quantity is power or amplitude.
- Compare theoretical results with datasheets, measured behavior, and the operating frequency range.
Limitations and Assumptions
The actual load response depends on switching rate, waveform low level, output impedance, filter, inductance, and load behavior. Average voltage does not imply the same behavior as a steady DC supply for every device. Check electrical ratings and use an oscilloscope for waveform verification.
Signal calculations describe a model, not a complete measurement of a physical system. Propagation medium, component tolerance, noise, impedance mismatch, bandwidth, and instrument limitations may not be represented by the inputs.
Frequently Asked Questions
What is duty cycle?
It is the percentage of one period during which the waveform is high.
Does a 50% duty cycle always mean half the high voltage?
Only for a waveform switching between that high level and zero; other low levels change the average.
Does this calculate PWM frequency?
No. It calculates an ideal average voltage from voltage and duty cycle.
Is wavelength always the free-space value?
No. The medium changes propagation speed, so a cable or material can have a shorter wavelength than free space.
Does a sampling calculation guarantee a clean digital signal?
No. Filtering, noise, clock accuracy, converter performance, and signal bandwidth also matter.