| Unit | Symbol | Equivalent | Common Applications |
|---|---|---|---|
| Farad | F | Base unit | Supercapacitors, very large energy storage |
| Millifarad | mF | 10-3 F = 1,000 μF | Large electrolytic capacitors, power filtering |
| Microfarad | μF | 10-6 F = 1,000 nF | Power supply filtering, coupling, timing circuits |
| Nanofarad | nF | 10-9 F = 1,000 pF | Signal coupling, bypass capacitors |
| Picofarad | pF | 10-12 F | RF circuits, high-frequency applications |
The first two digits represent significant figures, and the third digit is the multiplier (power of 10).
A number followed by a letter, where the letter represents a multiplier.
Includes voltage rating, capacitance value, and tolerance in one code.
Common EIA voltage codes used in combined capacitor markings:
The dimensional formula for capacitance is [M-1 L-2 T4 I2].
Capacitance is defined as the ratio of charge (Q) to voltage (V): C = Q/V
Since charge has dimensions [I·T] and voltage has dimensions [M·L2·T-3·I-1], capacitance has dimensions:
C = [I·T] / [M·L2·T-3·I-1] = [M-1·L-2·T4·I2]
| μF (Microfarad) | nF (Nanofarad) | pF (Picofarad) | Common Applications |
|---|---|---|---|
| 1000 μF | 1,000,000 nF | 1,000,000,000 pF | Large filter capacitors |
| 470 μF | 470,000 nF | 470,000,000 pF | Power supply smoothing |
| 220 μF | 220,000 nF | 220,000,000 pF | Audio coupling |
| 100 μF | 100,000 nF | 100,000,000 pF | Decoupling capacitors |
| 47 μF | 47,000 nF | 47,000,000 pF | Timing circuits |
| 22 μF | 22,000 nF | 22,000,000 pF | Audio applications |
| 10 μF | 10,000 nF | 10,000,000 pF | General purpose |
| 4.7 μF | 4,700 nF | 4,700,000 pF | Signal coupling |
| 2.2 μF | 2,200 nF | 2,200,000 pF | Filter circuits |
| 1 μF | 1,000 nF | 1,000,000 pF | Bypass capacitors |
| 0.68 μF | 680 nF | 680,000 pF | AC coupling |
| 0.47 μF | 470 nF | 470,000 pF | Tone controls |
| 0.33 μF | 330 nF | 330,000 pF | Cross-over networks |
| 0.22 μF | 220 nF | 220,000 pF | Snubber circuits |
| 0.15 μF | 150 nF | 150,000 pF | Motor starting |
| 0.1 μF | 100 nF | 100,000 pF | Ceramic bypass |
| 0.068 μF | 68 nF | 68,000 pF | High frequency bypass |
| 0.047 μF | 47 nF | 47,000 pF | Signal processing |
| 0.033 μF | 33 nF | 33,000 pF | Audio filters |
| 0.022 μF | 22 nF | 22,000 pF | RF coupling |
| 0.015 μF | 15 nF | 15,000 pF | Oscillator circuits |
| 0.01 μF | 10 nF | 10,000 pF | Ceramic disc |
| 0.0068 μF | 6.8 nF | 6,800 pF | VHF circuits |
| 0.0047 μF | 4.7 nF | 4,700 pF | Tuning circuits |
| 0.0033 μF | 3.3 nF | 3,300 pF | RF bypass |
| 0.0022 μF | 2.2 nF | 2,200 pF | High frequency |
| 0.0015 μF | 1.5 nF | 1,500 pF | Crystal oscillators |
| 0.001 μF | 1 nF | 1,000 pF | HF applications |
| - | 0.68 nF | 680 pF | RF tuning |
| - | 0.47 nF | 470 pF | Variable tuning |
| - | 0.33 nF | 330 pF | Trimmer capacitors |
| - | 0.22 nF | 220 pF | Antenna tuning |
| - | 0.15 nF | 150 pF | VHF/UHF circuits |
| - | 0.1 nF | 100 pF | High Q circuits |
| - | 0.068 nF | 68 pF | Microwave circuits |
| - | 0.047 nF | 47 pF | Ultra high frequency |
| - | 0.033 nF | 33 pF | Precision timing |
| - | 0.022 nF | 22 pF | Clock circuits |
| - | 0.015 nF | 15 pF | Crystal references |
| - | 0.01 nF | 10 pF | Very high frequency |
0.1 μF = 100 nF = 100,000 pF
10 nF = 0.01 μF = 10,000 pF
1000 pF = 1 nF = 0.001 μF
47 μF = 47,000 nF = 47,000,000 pF
Capacitance is a measure of a capacitor's ability to store an electric charge. The SI unit of capacitance is the farad (F), named after the English physicist Michael Faraday.
A capacitor with a capacitance of one farad can store one coulomb of charge when a potential difference of one volt is applied across its terminals: C = Q/V.
In practical electronic circuits, capacitors typically range from picofarads (pF) to microfarads (μF), with specialized applications using larger values.