Potential Difference Across Capacitor Calculator

Enter capacitor values and select the known data. Check steady, energy, and timed charging cases. Save reports for design notes and lab records fast.

Calculator Inputs

Example Data Table

Case Known values Formula Expected voltage
Charge and capacitance Q = 220 uC, C = 47 uF V = Q / C 4.680851 V
Energy and capacitance E = 12 mJ, C = 47 uF V = √(2E / C) 22.596 V
RC charging Vs = 12 V, V0 = 0 V, R = 10 kohm, C = 47 uF, t = 25 ms V(t) = Vs + (V0 - Vs)e^(-t/RC) 0.621 V

Formula Used

Voltage from charge: V = Q / C

Voltage from energy and capacitance: V = √(2E / C)

Voltage from energy and charge: V = 2E / Q

Charging voltage: V(t) = Vs + (V0 - Vs)e-t/RC

Discharging voltage: V(t) = V0e-t/RC

Series capacitance: Ceq = 1 / Σ(1/Ci)

Parallel capacitance: Ceq = ΣCi

How To Use This Calculator

Select the calculation type first. Enter only the values needed for that case. Choose the correct unit beside each input. For series or parallel capacitor banks, type capacitor values separated by commas. Press calculate. Review the result box above the form. Use CSV or PDF export for records.

Capacitor Voltage Planning

A capacitor stores charge on two separated plates. The voltage between those plates is the potential difference. It rises when more charge is stored. It falls when capacitance is larger. This calculator helps compare those cases with practical circuit inputs.

Why Potential Difference Matters

Capacitor voltage is important in filters, timing circuits, power supplies, motor drives, and sensor boards. A small error can stress parts. A high voltage can exceed the rated limit. A low voltage can stop a circuit from working as planned. Clear calculation helps before testing hardware.

Main Calculation Ideas

The direct relation is simple. Voltage equals charge divided by capacitance. Energy can also define voltage. When stored energy and capacitance are known, voltage comes from the square root of twice energy divided by capacitance. When energy and charge are known, voltage equals twice energy divided by charge. These forms are useful in laboratory work.

Advanced Circuit Use

Real circuits often change with time. In a charging circuit, the capacitor moves toward the supply voltage. The speed depends on resistance and capacitance. Their product is the time constant. After one time constant, the capacitor has moved about 63 percent toward its final value. After five constants, it is nearly settled. Discharge uses the same exponential behavior.

Series And Parallel Cases

Capacitors in series share the same charge. Their voltages can differ. A smaller capacitance gets a larger voltage share. Capacitors in parallel share the same voltage. Their total capacitance is the sum of all values. The tool supports both arrangements using a comma separated list.

Practical Accuracy Tips

Use units carefully. Microfarads and nanofarads differ greatly. Convert charge, energy, resistance, and time before judging results. Always compare the answer with the capacitor voltage rating. Add a safety margin for ripple, spikes, and tolerance. Electrolytic capacitors also need correct polarity. For critical designs, verify with measurements and the component data sheet.

Result Review

The result box shows voltage, charge, stored energy, time constant, and equivalent capacitance when they apply. It also creates export data for records. Use the example table to test the calculator first. Then enter your own values. This workflow makes capacitor selection easier and safer. Repeat checks when temperature or tolerances change.

FAQs

What is potential difference across a capacitor?

It is the voltage between the two capacitor plates. It depends on stored charge and capacitance. The direct relation is V = Q / C.

Can this calculator use microfarads?

Yes. It accepts farads, millifarads, microfarads, nanofarads, and picofarads. Select the unit beside the capacitance input before calculating.

How is energy related to capacitor voltage?

Stored energy equals one half times capacitance times voltage squared. If energy and capacitance are known, voltage is found with V = √(2E / C).

What does RC time constant mean?

The time constant is resistance times capacitance. It shows how fast a capacitor charges or discharges in a simple resistor capacitor circuit.

Why do series capacitors have different voltages?

Series capacitors carry the same charge. Voltage equals charge divided by each capacitance. A smaller capacitor therefore gets a larger voltage share.

Why do parallel capacitors share one voltage?

Parallel capacitors are connected across the same two nodes. Their voltage is the same, while their charges can be different.

Can negative charge give negative voltage?

Yes. A negative charge value can produce negative voltage. The sign shows polarity direction based on the selected reference.

Should I compare the result with the voltage rating?

Yes. Always keep the calculated voltage below the capacitor rating. Use extra margin for ripple, switching spikes, temperature, and component tolerance.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.