The humble resistor is the lowest-cost component in our maker box, but it is also incredibly useful. Previously, we’ve shownhow to use resistorsin a project, but the focus of this guide is understanding the colored bands that wrap around the center of the resistor. These resistor color codes tell us exactly how many Ohms of current each unit handles.
How do we read a resistor color code? Why are some resistor color codes four bands and others five bands? What resistor do I need for an LED? We answer all of these questions and give you the tools to quickly calculate the correct resistor for all of your projects.
Common Resistor Color Codes and Their Uses
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| Resistor Type | 4-Band Color Code | 5-Band Color Code | Common Uses |
|---|---|---|---|
| 100 Ohm | Brown-Black-Brown-Gold | Brown-Black-Black-Black-Gold | LED Light Protection |
| 220 Ohm | Red-Red-Brown-Gold | Red-Red-Black-Black-Gold | LED Light Protection |
| 330 Ohm | Orange-Orange-Brown-Gold | Orange-Orange-Black-Black-Gold | LED Light Protection |
| 1K Ohm (1Kiloohm) | Brown-Black-Red-Gold | Brown-Black-Black-Brown-Gold | LED Protection, Voltage Divider |
| 4.7K Ohm | Yellow-Purple-Red-Gold | Yellow-Purple-Black-Brown-Gold | Pull-up/down resistor for I2C |
| 10k Ohm | Brown-Black-Orange-Gold | Brown-Black-Black-Red-Gold | Pull-up/down resistor |
| 100K Ohm | Brown-Black-Yellow-Gold | Brown-Black-Black-Orange-Gold | Bleed resistor for capacitor |
| 1 Megaohm | Brown-Black-Green-Gold | Brown-Black-Black-Yellow-Gold | Capacitive touch circuits |
Resistor Color Code: Quick Reference
Reading Resistor Color Codes Left to Right
Resistors have no polarity, so they can be used in any orientation in a circuit. But to identify the correct resistor color code values we need to understand the colored bands on the resistor.
On a typical four-band hobby level resistor, there are three colors in a group. These are the first, second significant figures and the multiplier. The final band is the resistor’s tolerance, a margin of error if you will.For the majority of hobbyists a tolerance of 5% (Gold) is perfect and common.
We only need the extra precision if we create sensitive circuits, for example audio and video projects.We can always spot the tolerance band as it is the only band printed on the “shoulder” of the resistor. Look for this band to identify the orientation of the resistor.
A five-band resistor has an additional band, a third significant figure, which affords a greater level of accuracy should a project require it. So we have three significant figures, a multiplier and the tolerance, which is singularly printed on the shoulder.
How to Read a Resistor Color Code
Let’s use a 220 Ohm resistor, which is commonly used with LED lights, as an example of how to read resistor color codes.
- The first significant figure is red, and using the decoder we can see that red has a value of 2.
- The second significant figure is also red,so that gives us 22.
- The multiplier is brown, and this decodes to 10.If we multiply 22 by 10 we get 220.
- The final band, tolerance, is gold.Gold is 5%, which means we can accept a resistance with a 5% margin of error.
For makers requiring greater precision there are also five band resistors which have a third significant figure. The extra figure provides clarity which can be essential in circuits sensitive to resistance for example scientific and engineering instruments.
Here is a five band 220 Ohm resistor and its resistor color code.
- The first significant figure is red, and using the decoder, we can see that red has a value of 2.
- The second significant figure is also red,so that gives us 22.
- The third significant figure is black, indicating 0. We now have 220.
- The multiplier is black, and this decodes to 1. If we multiply 220 by 1 we get 220.
- The final band, tolerance, is gold.Gold is 5%, which means we can accept a resistance with a 5% margin of error.
100 Ohm Resistor Color Code
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The 100 Ohm resistor is commonly used for LED protection. Best used with white, blue and green LEDs at 5V. 100 Ohm resistors can also be used with other colors but expect the brightness to differ as they are not the correct value.
100 Ohm resistors can be identified via the resistor color code ofBrown-Black-Brown-Goldand, for five band resistors,Brown-Black-Black-Black-Gold.
220 Ohm Resistor Color Code
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The 220 Ohm resistor is one of the most common ones that hobbyists will come across, because it is often used with LEDs. Without a 220 Ohm resistor, simple LEDs would consume too much current and quickly burn out. We are using the resistor to limit the current that the LED can use. (“The light that burns twice as bright, burns half as long”).The 220 Ohm resistor can be identified via resistor color codes ofRed-Red-Brown-Goldor Red-Red-Black-Black-Gold.
If we were to use a blue LED with a 3.2V forward voltage (the amount of voltage needed to get current to flow across a diode) and 10mA forward current (the maximum safe current you can continuously pass through the device without causing damage) on a 5V supply we would need a 180 Ohm resistor. Instead we can use a 220 Ohm resistor, 40 Ohms higher so our LED won’t be as bright, but it will be well protected.
330 Ohm Resistor Color Code
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The 330 Ohm resistor is also quite common, being found in starter electronics kits for the Arduino andRaspberry Pi Pico. The 330 Ohm resistor is also a viable candidate for most LEDs but some will start to look dimmer than others. We can also use a 330 Ohm resistor with a buzzer to drop the tone of buzzer from “annoying” to slightly less annoying.Adafruit’s NeoPixel guiderecommends protecting a GPIO pin by using a resistor (between 300 and 500 Ohms) between the data pin input and GPIO of your Raspberry Pi / Arduino.
A330 Ohm resistor can be identified via resistor color codes ofOrange-Orange-Brown-GoldorOrange-Orange-Black-Black-Gold.
1K Ohm Resistor Color Code
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The 1K Ohm (1 Kiloohm) resistor is normally the maximum resistance used for LEDs. Any LED that uses a 1K resistor will be dull, but will light up.The 1K Ohm resistor is commonly used to fine tune a circuit or pull up/down a data pin. A 1K resistor, along with a 2.2K resistor can be used to form avoltage dividerthat can drop 5V down to around 3.4V. This is useful when using 5V components on theRaspberry Pi’s3.3V GPIO.
A 1K Ohmresistor can be identified viaresistor color codes ofBrown-Black-Red-GoldorBrown-Black-Black-Brown-Gold.
4.7K Ohm Resistor Color Code
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The 4.7K Ohm resistor is useful for adding a pull-up resistor to the SDA and SCL pins of an I2C device. Adafruit’s Stemma QT boards have this built in, but should we use another brand of board, we would need to add a 4.7Kiloohmresistor to both of those pins. By doing this we guarantee that the I2C data is correctly and consistently sent to our device.
A 4.7K Ohmresistor can be identified viaresistor color codes ofYellow-Purple-Red-GoldorYellow-Purple-Black-Brown-Gold.
10K Ohm Resistor Color Code
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The 10K Ohm resistor is often used as a pull-up resistor for an input pin. For example on Arduinos we can use a 10K Ohm resistor topull-up an input pin, so that when the button is pressed, it pulls the input pin high with 5V, triggering an action in our code. We used a 10K Ohm resistor to pull-up the data pin on a DHT22 temperature sensor in ourprevious resistor reference.
A 10K Ohmresistor can be identified viaresistor color codes ofBrown-Black-Orange-GoldorBrown-Black-Black-Red-Gold.
100K Ohm Resistor Color Code
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100K Ohm resistors are at the uppermost limit of what most makers need. This is a lot of resistance in a small package but it has its uses. They are typically used as bleed resistors on a capacitor, to reduce the risk of a nasty zap or to tune a sensitive audio / video circuit.
A 100K Ohm resistor can be identified using the color code of Brown-Black-Yellow-Gold or Brown-Black-Black-Orange-Gold for a five band resistor.
1M Ohm Resistor Color Code
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This is a lot of resistance and most hobbyists / makers will never need it. We’ve used a 1M Ohm resistor with an Arduino to create a capacitive touch interface (our own Makey Makey). But most folks will never need one. However, the 1M Ohm resistor has color codes of Brown-Black-Green-Gold or Brown-Black-Black-Yellow-Gold.
A 1M Ohmresistor can be identified viaresistor color codes ofBrown-Black-Green-GoldorBrown-Black-Black-Yellow-Gold.
LED Brightness Resistor Calculator
We have a box full of LEDs, but what are the correct resistors for each color? To work this out we need to use a little math and luckily there is a calculation that we can use.
R is the resistor value that we need for our LED and, to work that out, we need to know the supply voltage (Vs), the forward voltage (Vf) and the forward current (If) of the LED. We can learn the Vf and If of an LED b referring to its datasheet. If not, here is a table of approximate values which can be used for general hobbyist circuits.
Typical LED Forward Voltages
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| LED Color | Vf Range (Volts) |
|---|---|
| Red | 1.8 - 2.1 |
| Orange / Amber | 1.9 - 2.2 |
| Yellow | 1.9 - 2.2 |
| Green | 2 - 3.1 |
| Blue | 3 - 3.7 |
| White | 3 - 3.4 |
Here is a quick resistor and LED reference for 3.3 and 5V microcontrollers.
3.3V LED Resistor Values By Light Color
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| Header Cell - Column 0 | White | Red | Blue | Yellow | Green |
|---|---|---|---|---|---|
| Supply Voltage (Vs) | 3.3V | 3.3V | 3.3V | 3.3V | 3.3V |
| Forward Voltage (Vf) | 3V | 2.2V | 3V | 1.8V | 3V |
| Forward Current (If) | 20mA | 20mA | 20mA | 20mA | 20mA |
| Resistor Needed | 150 Ohm | 55 Ohm | 150 Ohm | 75 Ohm | 150 Ohm |
5V LED Resistor Values By Light Color
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| Header Cell - Column 0 | White | Red | Blue | Yellow | Green |
|---|---|---|---|---|---|
| Supply Voltage (Vs) | 5V | 5V | 5V | 5V | 5V |
| Forward Voltage (Vf) | 3V | 2.2V | 3V | 1.8V | 3V |
| Forward Current (If) | 20mA | 20mA | 20mA | 20mA | 20mA |
| Resistor Needed | 100 Ohm | 140 Ohm | 100 Ohm | 160 Ohm | 100 Ohm |
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FAQs
What is the color code for a 220 ω 10% resistor? ›
So, the color code of the 220 - ohm resistor is RED - RED - BROWN.
What is the color code for 220 K Ohms? ›220K Ohm Resistor Color Code: Red, Red, Yellow, Golden. Resistance: 220K Ohm, Power Rating: 0.25 Watt, Approximate Maximum Current: 1.07mA .
How do you read a 10K resistor color code? ›10K Ohm Resistor Color Code
A 10K Ohm resistor can be identified via resistor color codes of Brown-Black-Orange-Gold or Brown-Black-Black-Red-Gold.
Answer: The color code is Red Red Black Gold in 5%.
What is a resistor 220 ohm? ›A 220-ohm resistor is an electronic component that is used to resist the flow of electricity in a circuit. Resistors are used in a wide variety of electronic circuits to control the flow of current and protect other components from damage. 220-ohm resistors are a commonly used resistance value in electronic circuits.
What color is a 10k resistor? ›A 10k ohm resistor has 4 color bands: brown, black, orange, and gold for 5% tolerance, respectively. The first two bands signify the digits while the third one is the multiplier while fourth are tolerance. This is true in the case of four bands 10k resistors.
What color is 220v? ›Red wires are secondary wires in 220-volt systems. They are often used in switch legs and to connect smoke detectors to home systems, particularly to power the triggers that set all the detectors off at once. Red wires can be connected to each other.
What is 10K resistor? ›Commonly used in breadboards and other prototyping applications, these 10K ohm resistors make excellent pull-ups, pull-downs and current limiters. These thick-lead versions of the resistors fit snugly into a breadboard with very little movement, so you should have few to no issues using them in your next project!
How many ohms is a 10k resistor? ›A “10k” resistor is probably a 10,000 Ohm resistor.
How do you read a resistor number code? ›The first two bands always denote the first two digits of the resistance value in ohms. On a three or four-band resistor, the third band represents the multiplier. This multiplier will basically shift your decimal place around to change your value from mega ohms to milliohms and anywhere in between.
What is the maximum value of a 220 ohm resistor with a 10 tolerance? ›
A 220 Ω resistor has a silver tolerance band. Tolerance = value of resistor x value of tolerance band = 220 Ω x 10% = 22 Ω 220 Ω stated resistance +/- 22 Ω tolerance means that the resistor could range in actual value from as much as 242 Ω to as little as 198 Ω.
Does it matter which way round a resistor goes? ›After all, many capacitors, which are sometimes confused for resistors, are polarized and must be placed properly within a circuit. But resistors have no polarity. Current passes equally through from either direction. That means you can't install them backward.
What is the letter and digit code for resistors? ›For resistances, the standard dictates the use of the uppercase letters L (for 10−3), R (for 100 = 1), K (for 103), M (for 106), and G (for 109) to be used instead of the decimal point.
What are the 5 bands on a 220 ohm resistor? ›220 ohm resistor color code 5 band is red - red - black - black - [Tolerance]. 20k resistor color code is red - black - orange - [Tolerance].
What can I use instead of a 220 ohm resistor? ›You can use the 560 Ohm or 1K resistors with your LED. It will be slightly less bright than with the 220 Ohm resistor but still plenty bright enough.
What is the maximum value of a 220 ohm resistor? ›Standard carbon film 220 ohm resistor with 5% precision and a max power rating of 0.25 watts.
Can I use 1k resistor instead of 10K? ›You can use any resistance from 1k to 10k with your LCD but the actual value depends on your choice and preferences.
What is the difference between 1k and 10K resistors? ›The 1K resistors limit how much current flows through the LEDs so they don't blow. The 10K resistors limit how much current flows into the capacitors, setting the "time constant" of the charging of the capacitors. This combination of resistor and capacitor is what sets how fast the LEDs flash.
Are resistor color codes universal? ›The color code for resistors is a universal method employed to signify a resistor's resistance value, tolerance, and its temperature coefficient for 6-band resistor.
What are the 3 standard colors for a grounded 220V circuit? ›- Positive – red wire.
- Negative – black wire.
- Ground – white or gray wire.
How do you know if you have 220V? ›
Most houses today have two 110 volt wires and one neutral wire running into the house from the local distribution system. These wires can run underground or above ground. If there are two 110 volt wires running to the house, then the house has 220 volt service and appliances, such as dryers and air conditioners.
How many volts is a 10K resistor? ›Example: How much voltage is dropped across a 10K ohm resistor which has 5mA flowing through it? The voltage dropped across the resistor is 50 volts, because E = IR = 5mA * 10K = 50 volts.
What does k mean for resistors? ›A 1.2K resistor is a resistor with a resistance of 1.2-kilo ohms. If you are a layman, then you may get confused. In simple words, when an electric current flows through the resistor, it will come across a resistance of 1.2 thousand ohms. The unit “k” represents the “kilo,” which means thousand.
How much voltage can a 10K resistor handle? ›| Resistance | 10K ohm | |
|---|---|---|
| Voltage | Maximum Operating | 350V |
| Polarization | None | |
| Operating Temp | -55C – +155C | |
| Package | Conformal Coated, Axial |
Hex color codes start with a pound sign or hashtag (#) and are followed by six letters and/or numbers. The first two letters/numbers refer to red, the next two refer to green, and the last two refer to blue. The color values are defined in values between 00 and FF (instead of from 0 to 255 in RGB).
What do the numbers on resistors mean? ›The Three and Four Digit Systems
In these systems, the first two or three digits indicate the numerical resistance value of the resistor and the last digit gives a multiplier. The number of the last digit indicates the power of ten by which to multiply the given resistor value.
The colour code used to denote the tolerance rating of a resistor is given as: Brown = 1%, Red = 2%, Gold = 5%, Silver = 10 % If resistor has no fourth tolerance band then the default tolerance would be at 20%.
What is the purpose of a 10k ohm variable resistor in a circuit? ›Variable resistors are widely used in electric circuits to adjust the value of current or voltage, since the resistance of variable resistors can be set to a certain value. Variable resistors allow you to adjust the value of voltage by changing the resistance and keeping current constant .
What color resistor is 200 ohm? ›200 Ohm Resistor Color Code: Red, Black, Brown, Golden. Resistance: 200 Ohm, Power Rating: 0.25 Watt, Approximate Maximum Current: 35.35mA .
What is the value of 10k ohm? ›Therefore the multiplier is 103 = 1,000. So the total value of the resistance given by the colors is 10 x 103 Ω = 10,000 Ω = 10kΩ.
What are the 4 types of resistors? ›
- Types of Resistors. There are many different types of resistors and they can be made from various materials, all of which have their own unique advantages and disadvantages. ...
- Resistive Materials. ...
- Metal Film Resistors. ...
- Wirewound Resistors. ...
- Metal Oxide Resistors. ...
- Metal Strip Resistors.
1 Answer. There is no particular formulae but the resistance using the color codes is like R= [(numbers) × (multiplier) ± (tolerance (%) )].
What are the resistor Colour code sums? ›The tolerance for gold is 5%. ⇒ The colour code = Red Red Brown and Gold for 5%.
What is the value of the 220 SMD resistor? ›The 3 digit SMD resistor code 220 stands for 22 Ω, in words: twenty-two Ohms resistance.
What happens if you use the wrong resistor? ›Power Dissipated by Resistor - What Can Go Wrong
If you exceed the power rating of a resistor, it may get extremely hot. If you continue to increase the current, the power dissipated will also increase. The resistor will continue to increase in temperature--and may even burst into flames--before it finally fails.
Answer and Explanation: A resistor is a device which is responsible for the reduced strength of current when connected in a circuit. If a resistor is changed in the opposite direction of the current, then the sign convention of the change in potential difference is always positive.
Why are there two symbols for a resistor? ›The real part represent the resistance & the imaginary part represents the reactance. This component converts the electrical energy into heat energy. The current flow through the heating element generates heat energy due to its resistance. These both symbols represent a protection resistor.
What is 4 digit resistor code? ›Resistor Code Format
Similar to the three digit EIA, the four digit format uses the beginning values to indicate the significant digits while the last digit is the multiplier. 'R' is used to indicate the position of a decimal point. The four digit format allows for higher precision.
The resistor symbol as a kind of identification is unique to each type of resistor. There are many types of resistors, which can be divided into fixed resistors, variable resistors, special resistors, high-power resistors, low-power resistors, etc. They basically have different symbols for representation.
What are the possible colors of a resistor that has a resistive value of 220 ω with 20 tolerance? ›
Red, Red, Brown, Gold is the most appropriate option.
What is the voltage of 220 ohm resistor? ›Value of the resistor is R = 220 Ω and the current through the resistor is I = 5.6 mA . It is to be noted that 1 mA = 10 − 3 A . Conclusion: Therefore, the voltage across the resistor is V = 1.232 V .
What color is a 240 ohm resistor? ›240 Ohm Resistor Color Code: Red, Yellow, Black, Black, Brown. Resistance: 240 Ohm, Power Rating: 0.25 Watt, Approximate Maximum Current: 32.28mA .
What will be the current if the voltage is 220 V and 10 ohm resistance? ›Hence you must check out the details below Resistance, R = ? Current, = 10 A , Voltage, V = 220 volts. According to Ohm's law V = IR , or R = V/I = 220/10 = 22.
What does 220 voltage mean? ›220V is a particular level of electrical potential from a power source, or in simpler terms, the strength of the push given to make electrons flow through an electrical cable. 220V is the standard household voltage in dozens of countries, including China, Saudi Arabia, Chile, Egypt, the U.A.E, and South Korea.
What color is a 20K ohm resistor? ›20K Ohm Resistor Color Code: Red, Black, Orange, Golden. Resistance: 20K Ohm, Power Rating: 0.25 Watt, Approximate Maximum Current: 3.54mA .
What color code is a 250 ohm resistor? ›250 = Red-Green-Brown.
What is a 250 Ohm resistor? ›Most commonly a 250-Ohm resistor is used to convert the loop current back to a voltage.
What color is resistance 270 Ohm? ›270 Ohm Resistor Color Code: Red, Violet, Brown, Golden. Resistance: 270 Ohm, Power Rating: 1 Watt, Approximate Maximum Current: 60.86mA .