470 capacitor value
47 pF
47 pF · 0.047 nF · 0.000047 µF
| Marked code | 470 |
| Picofarads | 47 pF |
| Nanofarads | 0.047 nF |
| Microfarads | 0.000047 µF |
| Farads | 4.70e-11 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:
47 × 100 = 47 pF
So 470 is 47 followed by 0 zeros: 47 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 470 is stocked as 0.000047 µF and the two numbers look nothing alike.
What 47 pF 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 47 pF part covers several orders of magnitude:
| Frequency | Reactance |
|---|---|
| 50 Hz — mains | 67.73 MΩ |
| 1 kHz — audio | 3.39 MΩ |
| 100 kHz — switching | 33.86 kΩ |
| 10 MHz — RF | 338.63 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 470K carries a tolerance letter. It is not part of the value:
| Letter | Tolerance | 47 pF means |
|---|---|---|
470J | ±5% | 44.65 pF to 49.35 pF |
470K | ±10% | 42.3 pF to 51.7 pF |
470M | ±20% | 37.6 pF to 56.4 pF |
470Z | +80% / −20% | 37.6 pF to 84.6 pF |
A Z is worth knowing about. +80%/−20% is a real tolerance on cheap high-permittivity ceramics, and it means a part marked 470Z can legitimately be anything from 37.6 pF to 84.6 pF. Those go in decoupling positions where only the rough size matters, never in a timing or filter position.
Where 47 pF turns up
Tens of picofarads is the crystal load range: the two capacitors either side of a quartz crystal that set it oscillating at its marked frequency. Also RF tuning and the compensation capacitor round a fast op-amp.
Frequently asked questions
What is the value of a 470 capacitor?
47 pF — 47 pF · 0.047 nF · 0.000047 µF. The first two digits are the value in picofarads and the third is how many zeros follow, so 470 is 47 followed by 0 zeros = 47 pF.
What is a 470 capacitor in µF?
0.000047 µF. Going from picofarads to microfarads is six decimal places, which is where most of the confusion with these codes comes from — 47 pF, 0.047 nF and 0.000047 µF are the same capacitor written three ways.
What does the letter after 470 mean?
Tolerance. 470K is ±10%, 470J is ±5% and 470M is ±20% — so a 470K is anywhere from 42.3 pF to 51.7 pF 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 470 capacitor at 1 kHz?
3.39 MΩ. Reactance is 1 ÷ (2πfC), so it falls as the frequency rises: the same part is 33.86 kΩ at 100 kHz and 338.63 Ω at 10 MHz.
Nearby codes
- 560 capacitor — 56 pF
- 680 capacitor — 68 pF
- 820 capacitor — 82 pF
- 101 capacitor — 100 pF
- 121 capacitor — 120 pF
- 151 capacitor — 150 pF
- 181 capacitor — 180 pF
- 221 capacitor — 220 pF
- 271 capacitor — 270 pF
- 331 capacitor — 330 pF