The 6.8 kΩ (6,800 ohm) resistor color code depends on the tolerance band format you are holding. For a standard 4-band resistor, the sequence is Blue, Gray, Red, Gold. For a precision 5-band resistor, the sequence is Blue, Gray, Black, Brown, Gold (or Brown for 1% tolerance). If you are working with surface-mount (SMD) components, the stamped code is 682.
The Complete 6.8 k Resistor Color Code Reference Table
Use this table to verify the bands on your bench. 6.8 kΩ is a standard value in the E24 series, meaning it is mass-produced in both wide (5%) and tight (1%) tolerances.
| Format | Band 1 (Digit) | Band 2 (Digit) | Band 3 (Digit/Mult) | Band 4 (Mult/Tol) | Band 5 (Tol) | SMD Equivalent |
|---|---|---|---|---|---|---|
| 4-Band (5%) | Blue (6) | Gray (8) | Red (×100) | Gold (±5%) | N/A | 682 |
| 4-Band (10%) | Blue (6) | Gray (8) | Red (×100) | Silver (±10%) | N/A | 682 |
| 5-Band (1%) | Blue (6) | Gray (8) | Black (0) | Brown (×10) | Brown (±1%) | 6801 (E96) |
| 5-Band (2%) | Blue (6) | Gray (8) | Black (0) | Brown (×10) | Red (±2%) | 682 |
What Each Band Means in Practice (And the Universal Standard)
To understand why the colors map to 6,800 ohms, break down the math based on the IEC 60062 standard.
- Band 1 (Blue): First significant digit = 6.
- Band 2 (Gray): Second significant digit = 8.
- Band 3 (Red or Black): In a 4-band resistor, Red is the multiplier (×10² or 100). 68 × 100 = 6,800. In a 5-band resistor, the third band is the third significant digit (Black = 0), making the base number 680. The fourth band (Brown) becomes the multiplier (×10¹ or 10). 680 × 10 = 6,800.
- Final Band (Gold/Brown): Tolerance. Gold means the actual resistance can vary by ±5% (between 6,460Ω and 7,140Ω). Brown means ±1% (between 6,732Ω and 6,868Ω).
Rows People Get Wrong: Faded Bands and Tolerance Traps
Even experienced techs misread resistors when bench lighting is poor or components are old. Here are the specific failure modes for the 6.8 kΩ value:
Trap 1: Gray (8) vs. Violet (7)
Under warm incandescent or yellowed LED bench lights, the gray band on a carbon film resistor frequently looks violet. If you misread gray as violet, you will calculate 6.7 kΩ instead of 6.8 kΩ. While close, this 1.5% error can throw off precision op-amp gain stages or RC oscillator timings. Fix: Take the resistor to a north-facing window or use a 5000K daylight LED lamp to verify the gray band.
Trap 2: The Multiplier Confusion (Red vs. Brown)
People often grab a 680Ω resistor thinking it is 6.8kΩ. Why? They mix up the 4-band multiplier (Red = ×100) with the 5-band multiplier (Brown = ×10). If you are holding a 4-band resistor and the third band is Brown, you have 68 × 10 = 680Ω, not 6.8kΩ. Always count the total number of bands before assigning the multiplier.
Trap 3: Reading Direction on 5-Band Resistors
On 5-band metal film resistors, the spacing between the bands is often perfectly uniform. If you read it backward, Brown-Brown-Black-Gray-Blue translates to 110 × 10⁸ (11 GΩ) — an obvious error, but one that causes momentary panic. Rule of thumb: The tolerance band (Gold, Silver, Brown, Red) is always on the far right and usually spaced slightly further apart from the others.
Decision Path: Which 6.8kΩ Resistor Should You Buy?
Stop guessing which variant to add to your cart. Follow this decision tree to select the exact part number for your application.
| Your Application | Required Spec | Concrete Part Number to Buy | Approx. Cost (Reel) |
|---|---|---|---|
| General DIY / Arduino / LED Pull-ups Where exact value doesn't matter, just need a safe current limit. |
1/4W, 5% Tolerance, Carbon Film (Axial) | Yageo CFR-25JR-52-6K8 | ~$0.008 / unit |
| Precision ADC / Audio Crossovers / Sensor Bridges Where 5% drift will cause audible noise or measurement errors. |
0.6W, 1% Tolerance, Metal Film (Axial) | Vishay MRS25000C6801FCT00 | ~$0.045 / unit |
| High-Density PCB / SMD Rework Automated pick-and-place or tight board real estate. |
0603 Package, 1% Tolerance, Thick Film | Panasonic ERJ-3EKF6801V | ~$0.012 / unit |
Default Recommendation: If you are stocking a general-purpose bench kit and only want to buy one type, buy the Vishay MRS25 1% Metal Film series. The price difference between 5% carbon and 1% metal film is less than a penny per unit in bulk, but metal film offers vastly superior temperature stability (±50ppm/°C) and lower thermal noise.
Safe Interpretation When Markings Are Faded or Missing
Old carbon composition resistors from the 1970s and 80s often suffer from 'baked' bodies where the brown body darkens and the color bands bleed into the substrate. If you cannot confidently read the 6.8 kΩ color code, you must measure it. However, you must follow strict bench protocols to avoid false readings.
If you probe a 6.8 kΩ resistor while it is still soldered into a PCB, you are not measuring the resistor. You are measuring the Thevenin equivalent resistance of the entire parallel circuit network. A 6.8k resistor in parallel with a 10k semiconductor junction will read around 4.0k on your multimeter, leading you to falsely conclude the component has drifted or failed.
The Correct Desolder-and-Measure Protocol
- Isolate: Use a soldering iron and desoldering wick to lift at least one leg of the resistor completely out of the PCB pad. You do not need to remove it entirely; just break the electrical connection on one side.
- Zero the Meter: Touch your multimeter probes together. Note the lead resistance (usually 0.2Ω to 0.5Ω on cheap test leads). For a 6,800Ω measurement, this is negligible, but it is good practice.
- Measure and Wait: Touch the probes to the exposed metal leads (not the painted body). If using an auto-ranging DMM, wait a full 2-3 seconds. Auto-ranging meters often flash a lower value before settling on the correct 6.81k reading.
- Verify against Tolerance: If your meter reads 7.05k, and the resistor is a 5% tolerance part (Gold band), 7.05k is within the acceptable 6.46k - 7.14k window. The resistor is fine; your circuit issue lies elsewhere. If it reads 4.5k, the carbon element has cracked internally or suffered thermal runaway — bin it and solder in a fresh Vishay MRS25 replacement.
