Capacitor Code & Charge Calculator

The first two digits are the capacitance value; the third is the multiplier (power of 10) in picofarads. For example, '104' = 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF. '472' = 47 × 10² = 4,700 pF = 4.7 nF. The tolerance letter follows (J=±5%, K=±10%, M=±20%).

1 µF (microfarad) = 1,000 nF = 1,000,000 pF. 1 nF (nanofarad) = 1,000 pF. Common capacitor values range from picofarads (pF) in RF circuits, nanofarads (nF) in filter circuits, to microfarads (µF) in power supply filtering, and millifarads to farads in supercapacitors.

Energy (joules) = ½ × C × V². For a 100µF capacitor charged to 100V: E = 0.5 × 0.0001 × 100² = 0.5 joules. While this sounds small, a capacitor can release this energy in microseconds, creating enormous instantaneous power — which is why charged capacitors are dangerous even when disconnected from power.

The time constant τ (tau) = R × C. After one time constant, a capacitor charges to 63.2% of the supply voltage (or discharges to 36.8% of initial voltage). After 5τ, the capacitor is considered fully charged or discharged (99.3%). This determines the speed of RC filters, timers, and pulse-shaping circuits.

Ceramic: small, stable, for decoupling and high-frequency use. Electrolytic (aluminum/tantalum): large capacitance, polarized, for power supply filtering. Film (polyester, polypropylene): precise, low loss, for audio and timing. Supercapacitors (EDLC): very large capacitance, used as energy storage. Each type has different voltage ratings, temperature stability, and ESR characteristics.