Resistors are common electrical components found in many electronic circuits. They are used to reduce current flow and lower voltage levels within a circuit. Resistors have color coded bands on them that indicate their resistance value in ohms as well as their tolerance. Identifying the resistor value by reading the color bands is an essential skill for anyone working with electronics. In this article, we will look at how to read the color bands on a 2.2 k ohm resistor to determine its exact value and tolerance.
Resistor Color Coding
The resistor color coding system has been standardized for many decades and is outlined as follows:
| Band | Meaning |
|---|---|
| 1st band | First significant figure of resistance value |
| 2nd band | Second significant figure of resistance value |
| 3rd band | Decimal multiplier |
| 4th band | Tolerance |
The first two bands indicate the first two significant figures of the resistor’s ohmic value. The third band is the multiplier that the first two figures must be multiplied by to arrive at the full value. Common multipliers are:
| Color | Multiplier |
|---|---|
| Black | 1 |
| Brown | 10 |
| Red | 100 |
| Orange | 1,000 |
| Yellow | 10,000 |
| Green | 100,000 |
| Blue | 1,000,000 |
| Violet | 10,000,000 |
| Gray | 100,000,000 |
| White | 1,000,000,000 |
The fourth band indicates the tolerance or precision of the resistor value. Common tolerances are:
| Color | Tolerance |
|---|---|
| Brown | 1% |
| Red | 2% |
| Green | 0.5% |
| Blue | 0.25% |
| Violet | 0.1% |
| Gray | 0.05% |
Reading a 2.2 kOhm Resistor
Now let’s apply the resistor color code system to read a 2.2 kohm resistor:
- 1st Band – Red – Signifies the number 2
- 2nd Band – Red – Also signifies the number 2
- 3rd Band – Red – The multiplier with a value of 100
- 4th Band – Gold – The tolerance of 5%
Looking at the first two bands, we see they are both red, indicating the first two significant figures of the resistance are 22.
The third band is also red, indicating the multiplier is 100.
Multiplying the first two figures by the multiplier gives us:
22 x 100 = 2,200 ohms
Therefore, a 2.2 kohm resistor will have color bands of:
Red, Red, Red, Gold
The gold band indicates a tolerance of +/- 5%. This means the actual resistance value should be within 2,200 ohms +/- 5%.
Resistor Tables
For quick reference, here are tables showing the full color codes for standard resistor values:
4-Band Resistor Color Code Table
| 1st Band | 2nd Band | 3rd Band | 4th Band | Resistance (Ω) | Tolerance |
|---|---|---|---|---|---|
| Red | Red | Red | Gold | 2,200 | ±5% |
| Brown | Black | Orange | Gold | 10,000 | ±5% |
| Brown | Black | Yellow | Gold | 100,000 | ±5% |
| Red | Red | Orange | Gold | 2,200,000 | ±5% |
5-Band Resistor Color Code Table
5-band resistors have an additional tolerance band:
| 1st Band | 2nd Band | 3rd Band | 4th Band | 5th Band | Resistance (Ω) | Tolerance |
|---|---|---|---|---|---|---|
| Red | Red | Black | Brown | Brown | 2,200 | ±1% |
| Brown | Black | Green | Blue | Green | 1,000,000 | ±0.5% |
| Orange | Orange | Yellow | Violet | Red | 3,300,000 | ±2% |
These tables provide a quick reference for determining resistor values from their color bands. Referring to such tables saves the trouble of decoding each individual resistor from scratch.
Conclusion
Understanding resistor color coding is essential for anyone working with electronic circuits. A 2.2 kohm resistor can be easily identified from its red, red, red, gold band pattern. The first two red bands indicate the significant figures 22, the third red band shows a multiplier of 100, giving us a nominal value of 2,200 ohms. The gold band indicates a tolerance of ±5%. Being able to quickly read resistor values by their color bands is an important skill that comes in handy for technicians, engineers, hobbyists, and anyone involved in circuit design or analysis.
