The capacitor colour code is a legacy marking system used primarily on ceramic disc, tubular, and film capacitors to indicate capacitance in picofarads (pF), tolerance, and temperature coefficient. Unlike modern surface-mount components that use 3-digit alphanumeric codes (like "104" for 100,000 pF), vintage and military-spec through-hole capacitors rely on painted bands. The base unit for these color bands is always the picofarad (pF).
The Complete Capacitor Colour Code Reference Table
Most ceramic and tubular capacitors use a 4-band system. Read the bands from top to bottom (or left to right, keeping the tolerance band on the right). The first two bands represent significant digits, the third is the multiplier, and the fourth is the tolerance.
| Band Colour | 1st Digit | 2nd Digit | Multiplier (pF) | Tolerance | Temp Coeff (ppm/°C) |
|---|---|---|---|---|---|
| Black | 0 | 0 | x1 | - | - |
| Brown | 1 | 1 | x10 | ±1% | -30 to -500 |
| Red | 2 | 2 | x100 | ±2% | -75 |
| Orange | 3 | 3 | x1,000 | - | -150 |
| Yellow | 4 | 4 | x10,000 | - | -220 |
| Green | 5 | 5 | x100,000 | ±0.5% | -330 |
| Blue | 6 | 6 | - | - | -470 |
| Violet | 7 | 7 | - | - | -750 |
| Grey | 8 | 8 | - | +80%, -20% | - |
| White | 9 | 9 | - | ±5% (or ±10%) | +100 to -750 |
| Gold | - | - | - | ±5% | - |
| Silver | - | - | - | ±10% | - |
Example: A capacitor with Brown (1), Black (0), Red (x100), and Gold (±5%) bands equals 10 x 100 = 1,000 pF (or 1 nF) with a 5% tolerance.
Regional Standards and the Rows People Get Wrong
While the table above covers the dominant North American EIA RS-359 standard for ceramics, international and legacy variants introduce critical differences. According to Electronics Tutorials, the international IEC 60062 standard harmonized much of this, but European manufacturers (like Philips and Mullard) often used a 3-band or 4-band system on film capacitors where the final band indicated working voltage rather than temperature coefficient (e.g., a red band for 250V, blue for 630V). If you are restoring a pre-1970s UK valve amplifier, do not trust the EIA ceramic table for tubular paper caps; cross-reference the manufacturer’s specific schematic.
- The Multiplier Base Unit: Beginners read "Brown-Black-Red" as 10 x 100 = 1000 and assume microfarads. It is always picofarads. 1000 pF = 1 nF = 0.001 μF.
- Gold and Silver as Multipliers: In resistor codes, Gold means divide by 10. In capacitor codes, Gold and Silver are almost exclusively used for the Tolerance band, not as multipliers. If you see a gold band, it is the tolerance.
- The "Black Band" on Tantalums: A black band on a modern tantalum capacitor does not mean a digit of zero. It indicates the positive anode (polarity). Reversing a tantalum causes catastrophic thermal runaway and potential fire.
Safe Interpretation When Markings are Faded or Missing
Epoxy coatings on 1970s and 1980s ceramic capacitors are notorious for yellowing, chalking, and flaking off, taking the colour bands with them. If you are troubleshooting a vintage audio amp or radio and encounter an unmarked or faded capacitor, do not guess based on physical size.
Instead, desolder one leg of the component and measure it with a dedicated LCR meter (like the DER EE DE-5000 or Uni-Trend UT612). Multimeters with a "capacitance" setting often lack the test frequency resolution for small ceramics. For accurate readings:
- Set the LCR meter test frequency to 1 kHz for capacitors >10 nF.
- Set the test frequency to 100 kHz or 1 MHz for capacitors <1 nF to overcome parasitic lead inductance.
If the capacitor is completely degraded (measuring open or highly lossy) and you must substitute it, match the dielectric type. If the original was in a timing or filter circuit, replace it with a modern C0G/NP0 ceramic (which has a near-zero temperature coefficient, matching the old "black" or "brown" tempco bands). If it was just a bypass/decoupling cap, a standard X7R is perfectly acceptable.
Frequently Asked Questions
How do I read a 5-band capacitor colour code?
A 5-band code is typically found on precision or military-spec tubular capacitors. The first three bands represent significant digits (1st, 2nd, and 3rd), the fourth band is the multiplier (in pF), and the fifth band is the tolerance or voltage rating. For example, Red-Red-Red-Orange-Silver translates to 2-2-2 x 1,000 = 222,000 pF (222 nF) with a ±10% tolerance.
Is the capacitor colour code the same as the resistor colour code?
No. While the first two digit colours (Black=0 through White=9) are identical, the base unit differs. Resistor codes calculate in Ohms, while capacitor colour codes calculate in picofarads (pF). Furthermore, the tolerance and temperature coefficient bands on capacitors use different colour assignments than the standard EIA resistor tolerance chart.
What does a black band mean on a tantalum capacitor?
On modern solid tantalum capacitors (which usually look like small coloured epoxy drops rather than banded cylinders), a single black band or stripe denotes the positive terminal. This is a critical safety distinction. According to All About Circuits, applying reverse voltage to a tantalum capacitor breaks down the tantalum pentoxide dielectric layer, resulting in a dead short, extreme heat, and often a violent pop or fire.
Why do modern capacitors use printed numbers instead of colour bands?
The transition away from colour bands began in the 1980s with the rise of Multi-Layer Ceramic Capacitors (MLCCs) and automated pick-and-place manufacturing. Colour bands require manual orientation or complex optical sorting. The modern 3-digit alphanumeric code (e.g., "104" for 10 x 10^4 pF) is much cheaper to laser-print or stamp directly onto flat component bodies, and it is easier for automated optical inspection (AOI) cameras to verify on high-speed SMT assembly lines.
