Enter the load (discharge) current, ripple frequency, and capacitance into the calculator to estimate the capacitor ripple voltage. This calculator helps in designing power supplies and electronic circuits that require stable voltage levels.

Capacitor Ripple Voltage Calculator

Enter any 3 values to calculate the missing variable

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Capacitor Ripple Voltage Formula

The following approximate formula is used to estimate the capacitor peak-to-peak ripple voltage for a rectifier/reservoir-capacitor power supply under (roughly) constant load current:

\Delta V_{pp} = \frac{I}{f \cdot C}

Variables:

  • ΔVpp is the peak-to-peak ripple voltage (V)
  • I is the load (discharge) current drawn from the capacitor (A)
  • f is the ripple frequency (Hz) (for full-wave rectification, f is typically 2× the line frequency)
  • C is the capacitance (F)

To estimate the capacitor ripple voltage, divide the load current by the product of ripple frequency and capacitance.

What is Capacitor Ripple Voltage?

Capacitor ripple voltage is the periodic variation (often specified as peak-to-peak) on the DC output of a power supply caused by the reservoir capacitor charging near the peaks of the rectified waveform and discharging into the load between peaks. Excessive ripple voltage can lead to instability in electronic circuits and can affect the performance of components powered by the supply.

How to Calculate Capacitor Ripple Voltage?

The following steps outline how to calculate the Capacitor Ripple Voltage.

  1. First, determine the load (discharge) current (I) in amperes (A).
  2. Next, determine the ripple frequency (f) in hertz (Hz).
  3. Next, determine the capacitance (C) in farads (F).
  4. Next, gather the formula from above: ΔVpp = I / (f * C).
  5. Finally, calculate the Capacitor Ripple Voltage (ΔVpp) in volts (V).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Ripple (load) current (I) = 0.5 A

Ripple frequency (f) = 120 Hz

Capacitance (C) = 1000 μF (or 0.001 F)