Capacitor Calculator
Calculate capacitance, charge, and energy stored.
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How It Works
Calculates the energy stored in a capacitor: E = ½ × C × V². Capacitance (C) is in Farads, voltage (V) in volts. Energy is in joules. Capacitors store energy in an electric field.
Formula
Q = C x V, E = 0.5CV2Quick Reference
Common calculations — results you can verify instantly.
100µF at 12V
½×0.0001×144
0.0072J (7.2mJ)
1000µF at 5V
½×0.001×25
0.0125J
Parallel cap
C1 + C2
Total increases
Tips & Shortcuts
Capacitors in series: 1/C_total = 1/C1 + 1/C2 (like parallel resistors).
Capacitors in parallel: C_total = C1 + C2 (like series resistors).
Doubling voltage quadruples stored energy (energy scales with V²).
Common Mistakes
Exceeding capacitor voltage rating
Operating above rated voltage destroys the capacitor and can cause explosion. Always use capacitors rated higher than circuit voltage.
Confusing capacitance and capacitive reactance
Capacitance (F) is a physical property. Reactance (Ω) is opposition to AC current: Xc = 1/(2πfC).
Frequently Asked Questions
E = ½ × 0.0001 × 144 = 0.0072 joules (7.2 mJ). Small, but enough for camera flash circuits.
Capacitors charge/discharge almost instantly but store less energy. Batteries store more energy but charge/discharge slowly.
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