222 capacitor value
2.2 nF
2,200 pF · 2.2 nF · 0.0022 µF
| Marked code | 222 |
| Picofarads | 2,200 pF |
| Nanofarads | 2.2 nF |
| Microfarads | 0.0022 µF |
| Farads | 2.20e-9 F |
Reading the code
The three digits are not a part number. The first two are the value in picofarads and the third says what to do with them:
22 × 102 = 2,200 pF
So 222 is 22 followed by 2 zeros: 2,200 pF. The code is always in picofarads even when the part is sold in microfarads, which is the whole difficulty with it — a capacitor marked 222 is stocked as 0.0022 µF and the two numbers look nothing alike.
What 2.2 nF does at frequency
A capacitor's opposition to a signal is its reactance, 1 ÷ (2πfC), and it falls as the frequency rises. Over the range of frequencies a circuit can put across it, a 2.2 nF part covers several orders of magnitude:
| Frequency | Reactance |
|---|---|
| 50 Hz — mains | 1.45 MΩ |
| 1 kHz — audio | 72.34 kΩ |
| 100 kHz — switching | 723.43 Ω |
| 10 MHz — RF | 7.23 Ω |
Ten times the frequency is a tenth of the reactance, every time — which is why choosing a decoupling capacitor is really choosing the frequency band you want it to be low-impedance across, and why boards carry several sizes in parallel rather than one large one.
The letter after the number
A code like 222K carries a tolerance letter. It is not part of the value:
| Letter | Tolerance | 2.2 nF means |
|---|---|---|
222J | ±5% | 2.09 nF to 2.31 nF |
222K | ±10% | 1.98 nF to 2.42 nF |
222M | ±20% | 1.76 nF to 2.64 nF |
222Z | +80% / −20% | 1.76 nF to 3.96 nF |
A Z is worth knowing about. +80%/−20% is a real tolerance on cheap high-permittivity ceramics, and it means a part marked 222Z can legitimately be anything from 1.76 nF to 3.96 nF. Those go in decoupling positions where only the rough size matters, never in a timing or filter position.
Where 2.2 nF turns up
Single-figure nanofarads is audio filtering and snubbing across switch contacts. It is also the range where a capacitor stops being a precision component and starts being a bypass, depending on the dielectric it is made from.
Frequently asked questions
What is the value of a 222 capacitor?
2.2 nF — 2,200 pF · 2.2 nF · 0.0022 µF. The first two digits are the value in picofarads and the third is how many zeros follow, so 222 is 22 followed by 2 zeros = 2,200 pF.
What is a 222 capacitor in µF?
0.0022 µF. Going from picofarads to microfarads is six decimal places, which is where most of the confusion with these codes comes from — 2,200 pF, 2.2 nF and 0.0022 µF are the same capacitor written three ways.
What does the letter after 222 mean?
Tolerance. 222K is ±10%, 222J is ±5% and 222M is ±20% — so a 222K is anywhere from 1.98 nF to 2.42 nF and still in specification. A Z means +80%/−20%, which is not a mistake: some ceramic dielectrics really are that loose.
What is the impedance of a 222 capacitor at 1 kHz?
72.34 kΩ. Reactance is 1 ÷ (2πfC), so it falls as the frequency rises: the same part is 723.43 Ω at 100 kHz and 7.23 Ω at 10 MHz.
Nearby codes
- 272 capacitor — 2.7 nF
- 332 capacitor — 3.3 nF
- 392 capacitor — 3.9 nF
- 472 capacitor — 4.7 nF
- 562 capacitor — 5.6 nF
- 682 capacitor — 6.8 nF
- 822 capacitor — 8.2 nF
- 103 capacitor — 10 nF
- 123 capacitor — 12 nF
- 153 capacitor — 15 nF