축전기 계산기
무료 축전기 계산기. 정전용량, 전압, 주파수를 입력합니다.
축전기의 전하, 에너지, 리액턴스 및 RC 시간 상수를 계산합니다.
A capacitor is a device that stores electrical energy. This calculator computes charge (Q), energy (E), capacitive reactance (Xc), and RC time constant based on capacitance and voltage.
Key Formulas
- Charge: Q = C × V (Coulombs)
- Energy: E = 0.5 × C × V² (Joules)
- Reactance (AC): Xc = 1 / (2πfC) (Ohms)
- RC Time Constant: τ = R × C (seconds)
Parameters
- Capacitance: Stored charge per unit voltage (Farads). Common units: μF (1e-6 F), nF (1e-9 F), pF (1e-12 F)
- Voltage: Potential difference across capacitor (Volts)
- Frequency: AC frequency in Hz. Use 0 for DC.
How It Works
- Enter capacitance in Farads (use scientific notation or prefixes)
- Enter voltage applied to capacitor
- Optionally enter AC frequency (leave 0 for DC)
- Review charge, energy, reactance, and time constant
Common Values
- Electrolytic: 1–100 μF (high capacitance, polarized)
- Ceramic: 100 pF–100 μF (temperature-stable)
- Film: 100 nF–100 μF (precise, low loss)
Applications
- Power supplies: Filter ripple voltage
- Timing circuits: RC time constant determines frequency
- AC coupling: Block DC while passing AC
- Energy storage: Flash photography, power backup
- Impedance matching: AC networks
FAQ
Q: What does charge on a capacitor mean? A: Charge is the amount of electrical energy stored. A 1 μF capacitor at 10 V stores 10 μC (microcoulombs) of charge.
Q: Why does energy increase with voltage? A: Energy is proportional to V². Doubling voltage quadruples energy storage.
Q: What is capacitive reactance? A: Reactance (Xc) is the “resistance” a capacitor presents to AC. Higher frequency → lower reactance → easier AC passes.
Q: What is RC time constant? A: τ = R × C is the time for a capacitor to charge to 63% through a resistor R. Used in oscillators, timers, filters.
Q: Why use DC = 0 Hz? A: Capacitors block DC (infinite reactance at f=0). Set frequency to 0 to skip reactance calculation.