Pulse Width and PWM Calculator
Select a mode. The form shows only relevant inputs.
Ready-to-use presets
Load common timing values instantly.
Interactive waveform visualization
High time, low time, period, and duty cycle update together.
Signal comparison table
Compare several pulse signals side by side.
| Signal | Frequency | Duty cycle | Period | Pulse width | Low time | Action |
|---|
Example pulse calculations
Reference values for common applications.
| Application | Frequency | Duty cycle | Period | Pulse width | Typical purpose |
|---|---|---|---|---|---|
| Square wave | 1 kHz | 50% | 1 ms | 500 µs | Digital timing reference |
| RC servo center | 50 Hz | 7.5% | 20 ms | 1.5 ms | Neutral servo position |
| Motor PWM | 20 kHz | 35% | 50 µs | 17.5 µs | Quiet motor control |
| Infrared carrier | 38 kHz | 33% | 26.316 µs | 8.684 µs | Remote control transmission |
| 100 MHz clock | 100 MHz | 50% | 10 ns | 5 ns | High-speed digital logic |
| Fuel injector | 100 Hz | 30% | 10 ms | 3 ms | Injector opening command |
| Camera trigger | 10 Hz | 1% | 100 ms | 1 ms | External shutter control |
| Ultrasonic burst | 40 kHz | 50% | 25 µs | 12.5 µs | Transducer excitation |
Formula used
Core equations for timing, PWM, energy, and pulse sequences.
How to use this calculator
Follow these steps for reliable pulse calculations.
- Select the calculation mode matching your known values.
- Enter frequency, period, pulse width, duty cycle, or power.
- Choose the correct unit beside every measured value.
- Open advanced timer, servo, burst, or sequence modes when needed.
- Set decimal precision, notation style, and signal polarity.
- Press the calculation button to create detailed results.
- Review the formula, substitution, warnings, and waveform.
- Copy, print, share, or export the calculated values.
Understanding pulse width and duty cycle
A practical guide for digital timing and PWM work.
What pulse width means
Pulse width describes how long a signal remains active. Digital systems often call this interval high time. Active-low circuits reverse that interpretation. The calculator therefore includes a polarity option. Pulse width may use seconds or smaller units. Microseconds and nanoseconds appear frequently in electronics.
Period, frequency, and repetition rate
Period measures one complete signal cycle. Frequency counts completed cycles each second. These quantities are mathematical reciprocals. A higher frequency always produces a shorter period. Pulse repetition frequency uses the same relationship. Radar, lasers, and ultrasound often use that wording.
Duty cycle in PWM systems
Duty cycle compares active time with total period. A fifty percent waveform stays active half the cycle. PWM controllers vary this ratio intentionally. Motors use PWM for speed control. LEDs use PWM for brightness control. Power converters use PWM for energy regulation.
Timer register calculations
Microcontrollers generate PWM through hardware timers. A prescaler divides the incoming clock. An auto-reload register establishes the counting range. A compare register determines the switching point. Actual values can differ from requested values. Integer register limits cause that difference. Frequency and duty errors reveal the practical accuracy.
Servo and burst applications
Servo controllers encode position through pulse duration. The calculator interpolates between minimum and maximum pulses. Burst systems send grouped pulses with intentional gaps. Their overall duty cycle includes every burst gap. This differs from duty inside each individual pulse train.
Pulse energy and average power
Peak power applies only during each active pulse. Multiplying peak power by pulse duration gives pulse energy. Multiplying pulse energy by repetition frequency gives average power. These relationships matter for laser safety, radar transmitters, pulsed heating, and switching devices.
Choosing useful precision
Use enough digits to preserve meaningful timing information. Excess digits can imply false measurement accuracy. Engineering notation helps compare very small intervals. Automatic units improve readability across large ranges. Accurate pulse timing improves every modern electronic control system.
Frequently asked questions
Common questions about pulses, frequency, PWM, and timers.
What is pulse width?
Pulse width is the duration a signal remains active during one cycle. It is commonly measured in milliseconds, microseconds, nanoseconds, or picoseconds.
How is pulse width related to duty cycle?
Pulse width equals the period multiplied by duty cycle as a decimal. A 25% duty cycle uses one quarter of every period.
Can pulse width exceed the period?
No. A single pulse width cannot exceed its complete signal period. Such input would imply a duty cycle above 100%.
What is the difference between frequency and pulse repetition frequency?
They describe the same cycle rate in many systems. Pulse repetition frequency is preferred for pulsed radar, lasers, ultrasound, and triggering systems.
Why does a timer produce frequency error?
Timer registers accept integer counts only. The nearest valid count may create a slightly different frequency than the requested value.
Does active-low change the pulse duration?
No. It changes which voltage level represents the active state. The calculated timing stays identical, while the waveform display reverses levels.
How do I calculate pulse energy?
Multiply peak power in watts by pulse duration in seconds. The result is joules per pulse. Convert joules afterward when needed.
What pulse width does a hobby servo use?
Many hobby servos use roughly one to two milliseconds inside a twenty-millisecond frame. Always check the specific servo documentation before applying limits.
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