1 nF capacitor (0.001 µF)
A 1 nF capacitor is the same as 0.001 µF or 1,000 pF. On ceramic and film parts it is printed as the code 102; schematics often write 1n0 or 1n.
How a 1 nF capacitor is marked
| Style | Marking | Where you see it |
|---|---|---|
| 3-digit code | 102 | Ceramic discs, multilayer ceramics, film capacitors |
| Code + tolerance | 102J · 102K · 102M | ±5% · ±10% · ±20% |
| Code + voltage | 1H102K · 2A102J | 50 V · 100 V film capacitors |
| IEC 60062 letter code | 1n0 or 1n | Schematics, European parts (the letter is the decimal point) |
| Plain value | .001 (µF) on older parts | Older US parts and electrolytics — bare decimals are µF |
| SMD (0402–1206) | usually unmarked | Check the reel label or measure with an LCR meter |
1 nF in every unit
| Picofarads | 1,000 pF |
|---|---|
| Nanofarads | 1 nF |
| Microfarads | 0.001 µF |
| Farads | 1 × 10^-9 |
Reactance of 1 nF
A capacitor's opposition to AC falls as frequency rises: XC = 1 ÷ (2π f C). This tells you whether 1 nF passes or blocks a signal — a decoupling capacitor needs a low reactance at the noise frequency, a coupling capacitor at the lowest signal frequency.
| Frequency | Reactance XC |
|---|---|
| 50 Hz | 3.18 MΩ |
| 60 Hz | 2.65 MΩ |
| 1 kHz | 159 kΩ |
| 10 kHz | 15.9 kΩ |
| 100 kHz | 1.59 kΩ |
| 1 MHz | 159 Ω |
| 10 MHz | 15.9 Ω |
Real capacitors stop behaving like ideal ones above their self-resonant frequency, which depends on the package and lead length, so treat the high-frequency rows as an upper bound on performance.
RC time constant and filter corner with 1 nF
With a resistor R, the capacitor charges to 63% in one time constant τ = R × C and to over 99% in 5τ. The same pair makes a first-order low-pass or high-pass filter with corner frequency fc = 1 ÷ (2π R C).
| Resistor | τ = RC | 5τ (≈ full charge) | Corner fc |
|---|---|---|---|
| 100 Ω | 100 ns | 500 ns | 1.59 MHz |
| 1 kΩ | 1 µs | 5 µs | 159 kHz |
| 10 kΩ | 10 µs | 50 µs | 15.9 kHz |
| 100 kΩ | 100 µs | 500 µs | 1.59 kHz |
Choosing a 1 nF capacitor
| Usual dielectric | C0G/NP0 or X7R ceramic, polyester film |
|---|---|
| Common voltage ratings | 50–100 V |
| Neighbouring E6 values | 330 pF, 470 pF, 680 pF, 1.5 nF, 2.2 nF, 3.3 nF |
1 nF sits on the boundary between C0G and X7R ceramics: C0G parts are available and preferred for filters and timing where stability matters, X7R for general bypassing. Film capacitors marked 1n or 102 are common in audio and snubber circuits, often with a voltage code like 2A (100 V).
FAQ
What is the code for a 1 nF capacitor?
102. The first two digits (10) are picofarads and the third (2) is the number of zeros: 1,000 pF. In IEC letter notation it is written 1n0 or 1n.
Is 1 nF the same as 0.001 µF?
Yes. 1,000 pF = 1 nF = 0.001 µF; they are three names for the same capacitance.
What is the reactance of a 1 nF capacitor?
Xc = 1 ÷ (2π × f × C). At 1 kHz a 1 nF capacitor has 159 kΩ; at 50 Hz 3.18 MΩ.
What cutoff frequency does 1 nF give with 10 kΩ?
fc = 1 ÷ (2π × 10 kΩ × 1 nF) = 15.9 kHz, and the time constant τ = R × C = 10 µs.