Toolman

336 capacitor value

33 µF

33,000,000 pF · 33000 nF · 33 µF

Marked code336
Picofarads33,000,000 pF
Nanofarads33000 nF
Microfarads33 µF
Farads3.30e-5 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:

33 × 106 = 33,000,000 pF

So 336 is 33 followed by 6 zeros: 33,000,000 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 336 is stocked as 33 µF and the two numbers look nothing alike.

What 33 µF 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 33 µF part covers several orders of magnitude:

FrequencyReactance
50 Hz — mains96.46 Ω
1 kHz — audio4.82 Ω
100 kHz — switching48.2 mΩ
10 MHz — RF0.5 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 336K carries a tolerance letter. It is not part of the value:

LetterTolerance33 µF means
336J±5%31.35 µF to 34.65 µF
336K±10%29.7 µF to 36.3 µF
336M±20%26.4 µF to 39.6 µF
336Z+80% / −20%26.4 µF to 59.4 µF

A Z is worth knowing about. +80%/−20% is a real tolerance on cheap high-permittivity ceramics, and it means a part marked 336Z can legitimately be anything from 26.4 µF to 59.4 µF. Those go in decoupling positions where only the rough size matters, never in a timing or filter position.

Where 33 µF turns up

Microfarads and up is bulk energy storage: holding a rail up between switching cycles, smoothing a supply, or coupling a signal that goes down to a few hertz. Above about 10 µF ceramics give way to electrolytics and tantalums, which is why the code runs out here.

Frequently asked questions

What is the value of a 336 capacitor?

33 µF — 33,000,000 pF · 33000 nF · 33 µF. The first two digits are the value in picofarads and the third is how many zeros follow, so 336 is 33 followed by 6 zeros = 33,000,000 pF.

What is a 336 capacitor in µF?

33 µF. Going from picofarads to microfarads is six decimal places, which is where most of the confusion with these codes comes from — 33,000,000 pF, 33000 nF and 33 µF are the same capacitor written three ways.

What does the letter after 336 mean?

Tolerance. 336K is ±10%, 336J is ±5% and 336M is ±20% — so a 336K is anywhere from 29.7 µF to 36.3 µF 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 336 capacitor at 1 kHz?

4.82 Ω. Reactance is 1 ÷ (2πfC), so it falls as the frequency rises: the same part is 48.2 mΩ at 100 kHz and 0.5 mΩ at 10 MHz.

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