Capacitor Charge Calculator
RC circuit & energy calculator
Calculation Mode
Input Values
Capacitor Visualization
Charge vs Voltage
Energy vs Voltage
RC Circuit Parameters
Charge/Discharge at Time Points
| Time | Charging (V, Q) | Discharging (V, Q) |
|---|
Voltage vs Time
Charge vs Time
Capacitor Formulas
Common Capacitor Values
Reference table for common capacitor types and their typical applications
| Type | Typical Range | Voltage Rating | Applications |
|---|---|---|---|
| Ceramic | 1 pF - 100 μF | 6V - 10kV | Decoupling, filtering, timing |
| Electrolytic | 0.1 μF - 1 F | 6V - 500V | Power supply filtering, coupling |
| Tantalum | 0.1 μF - 1000 μF | 4V - 50V | Compact filtering, medical devices |
| Film | 100 pF - 100 μF | 50V - 2kV | Audio, high-frequency circuits |
| Supercapacitor | 0.1 F - 5000 F | 2.7V - 5.5V | Energy storage, backup power |
| Mica | 1 pF - 10 nF | 100V - 10kV | RF circuits, high-precision |
RC Time Constant Milestones
Percentage of final value reached at each time constant during charging
| Time | Charging (% of V₀) | Discharging (% of V₀) |
|---|---|---|
| 1τ | 63.2% | 36.8% |
| 2τ | 86.5% | 13.5% |
| 3τ | 95.0% | 5.0% |
| 4τ | 98.2% | 1.8% |
| 5τ | 99.3% | 0.7% |
Capacitor Tips
Voltage Rating
Always use capacitors with voltage rating higher than circuit voltage (at least 1.5x safety margin)
Polarity Matters
Electrolytic and tantalum capacitors are polarized - reverse polarity can cause explosion
Time Constant
After 5τ, capacitor is considered fully charged (99.3%) or discharged (0.7% remaining)
Discharge Safely
Large capacitors can store dangerous energy - always discharge through a resistor before handling
Understanding Capacitors
Capacitors are fundamental electronic components that store electrical energy in an electric field. They consist of two conductive plates separated by a dielectric (insulating) material. Capacitors are used in virtually every electronic circuit for filtering, coupling, decoupling, timing, and energy storage applications.
Capacitor Formulas
The fundamental formulas for capacitor calculations:
- Charge: Q = C × V (Coulombs = Farads × Volts)
- Energy: E = ½ × C × V² (Joules)
- RC Time Constant: τ = R × C (seconds)
- Charging: V(t) = V₀ × (1 - e^(-t/τ))
- Discharging: V(t) = V₀ × e^(-t/τ)
RC Circuit Behavior
In an RC (resistor-capacitor) circuit, the capacitor charges and discharges exponentially:
- 1τ (63.2%): After one time constant, capacitor reaches 63.2% of final voltage
- 2τ (86.5%): After two time constants, reaches 86.5%
- 3τ (95.0%): After three time constants, reaches 95.0%
- 5τ (99.3%): After five time constants, considered fully charged (99.3%)
Capacitor Types
Common capacitor types and their characteristics:
- Ceramic: Small, inexpensive, non-polarized, used for decoupling and filtering
- Electrolytic: High capacitance, polarized, used in power supplies
- Tantalum: Compact, stable, polarized, used in precision circuits
- Film: Stable, low loss, used in audio and high-frequency applications
- Supercapacitor: Very high capacitance, used for energy storage
Using This Calculator
Follow these steps:
- Step 1: Select calculation mode (Find Charge or Find Energy)
- Step 2: Enter capacitance value and select unit
- Step 3: Enter voltage across the capacitor
- Step 4: Optionally enter resistance for RC time constant
- Step 5: Click "Calculate" to see charge, energy, and time constant
- Step 6: View the capacitor visualization with charge indicators
- Step 7: Use the Charge/Discharge tab for RC circuit analysis
- Step 8: Check the Reference tab for capacitor types and formulas
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