682 capacitor value
6.8 nF
6,800 pF · 6.8 nF · 0.0068 µF
| Marked code | 682 |
| Picofarads | 6,800 pF |
| Nanofarads | 6.8 nF |
| Microfarads | 0.0068 µF |
| Farads | 6.80e-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:
68 × 102 = 6,800 pF
So 682 is 68 followed by 2 zeros: 6,800 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 682 is stocked as 0.0068 µF and the two numbers look nothing alike.
What 6.8 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 6.8 nF part covers several orders of magnitude:
| Frequency | Reactance |
|---|---|
| 50 Hz — mains | 468.1 kΩ |
| 1 kHz — audio | 23.41 kΩ |
| 100 kHz — switching | 234.05 Ω |
| 10 MHz — RF | 2.34 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 682K carries a tolerance letter. It is not part of the value:
| Letter | Tolerance | 6.8 nF means |
|---|---|---|
682J | ±5% | 6.46 nF to 7.14 nF |
682K | ±10% | 6.12 nF to 7.48 nF |
682M | ±20% | 5.44 nF to 8.16 nF |
682Z | +80% / −20% | 5.44 nF to 12.24 nF |
A Z is worth knowing about. +80%/−20% is a real tolerance on cheap high-permittivity ceramics, and it means a part marked 682Z can legitimately be anything from 5.44 nF to 12.24 nF. Those go in decoupling positions where only the rough size matters, never in a timing or filter position.
Where 6.8 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 682 capacitor?
6.8 nF — 6,800 pF · 6.8 nF · 0.0068 µF. The first two digits are the value in picofarads and the third is how many zeros follow, so 682 is 68 followed by 2 zeros = 6,800 pF.
What is a 682 capacitor in µF?
0.0068 µF. Going from picofarads to microfarads is six decimal places, which is where most of the confusion with these codes comes from — 6,800 pF, 6.8 nF and 0.0068 µF are the same capacitor written three ways.
What does the letter after 682 mean?
Tolerance. 682K is ±10%, 682J is ±5% and 682M is ±20% — so a 682K is anywhere from 6.12 nF to 7.48 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 682 capacitor at 1 kHz?
23.41 kΩ. Reactance is 1 ÷ (2πfC), so it falls as the frequency rises: the same part is 234.05 Ω at 100 kHz and 2.34 Ω at 10 MHz.
Nearby codes
- 822 capacitor — 8.2 nF
- 103 capacitor — 10 nF
- 123 capacitor — 12 nF
- 153 capacitor — 15 nF
- 183 capacitor — 18 nF
- 223 capacitor — 22 nF
- 273 capacitor — 27 nF
- 333 capacitor — 33 nF
- 393 capacitor — 39 nF
- 473 capacitor — 47 nF