When to use this calculator
Estimate capacitor voltage after an ideal RC discharge interval. Assumes discharge through the entered resistor without other current paths.
Explore the dc circuits & components calculators for other questions in this topic. For a related calculation, use the Capacitor Energy Calculator: Find stored energy in an ideal capacitor.
PUTTING IT INTO PRACTICE
Capacitor Discharge Voltage: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Initial voltage (V) | 10 |
| Resistance (Ω) | 1,000 |
| Capacitance (μF) | 1,000 |
| Elapsed time (s) | 0 |
| Result | 10 V |
- Check the input labels and enter the example values above.
- Apply the relationship: Voltage = initial voltage × exp(−time/(RC)).
- The result is 10 V, rounded for display.
How to interpret your result
Assumes discharge through the entered resistor without other current paths.
Ideal component models omit tolerances, heat and parasitic effects. Distinguish nominal energy from usable energy for batteries. Component ratings and installation requirements need separate manufacturer and design checks.
Frequently asked questions
Can these calculations select a safe installation rating?
No. They explain ideal relationships and do not include every thermal, protective or regulatory requirement.
When is the capacitor discharge voltage calculator useful?
Estimate capacitor voltage after an ideal RC discharge interval. Assumes discharge through the entered resistor without other current paths.
How do I use the capacitor discharge voltage calculator?
Enter initial voltage (v), resistance (ω), capacitance (μf), elapsed time (s). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Voltage = initial voltage × exp(−time/(RC)).
What should I check before using the result?
Assumes discharge through the entered resistor without other current paths.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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