Toolman

223 capacitor value

22 nF

22,000 pF · 22 nF · 0.022 µF

Marked code223
Picofarads22,000 pF
Nanofarads22 nF
Microfarads0.022 µF
Farads2.20e-8 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 × 103 = 22,000 pF

So 223 is 22 followed by 3 zeros: 22,000 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 223 is stocked as 0.022 µF and the two numbers look nothing alike.

What 22 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 22 nF part covers several orders of magnitude:

FrequencyReactance
50 Hz — mains144.69 kΩ
1 kHz — audio7.23 kΩ
100 kHz — switching72.34 Ω
10 MHz — RF723.4 mΩ

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 223K carries a tolerance letter. It is not part of the value:

LetterTolerance22 nF means
223J±5%20.9 nF to 23.1 nF
223K±10%19.8 nF to 24.2 nF
223M±20%17.6 nF to 26.4 nF
223Z+80% / −20%17.6 nF to 39.6 nF

A Z is worth knowing about. +80%/−20% is a real tolerance on cheap high-permittivity ceramics, and it means a part marked 223Z can legitimately be anything from 17.6 nF to 39.6 nF. Those go in decoupling positions where only the rough size matters, never in a timing or filter position.

Where 22 nF turns up

Tens of nanofarads is coupling between audio stages and the smaller decoupling capacitors on a logic board. A 10 nF part alongside a 100 nF one is a common pairing, the smaller of the two handling the frequencies the larger one is too slow for.

Frequently asked questions

What is the value of a 223 capacitor?

22 nF — 22,000 pF · 22 nF · 0.022 µF. The first two digits are the value in picofarads and the third is how many zeros follow, so 223 is 22 followed by 3 zeros = 22,000 pF.

What is a 223 capacitor in µF?

0.022 µF. Going from picofarads to microfarads is six decimal places, which is where most of the confusion with these codes comes from — 22,000 pF, 22 nF and 0.022 µF are the same capacitor written three ways.

What does the letter after 223 mean?

Tolerance. 223K is ±10%, 223J is ±5% and 223M is ±20% — so a 223K is anywhere from 19.8 nF to 24.2 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 223 capacitor at 1 kHz?

7.23 kΩ. Reactance is 1 ÷ (2πfC), so it falls as the frequency rises: the same part is 72.34 Ω at 100 kHz and 723.4 mΩ at 10 MHz.

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