The common-or-garden resistor is the bottom value element in our maker field, however it’s also extremely helpful. Beforehand, we’ve proven tips on how to use resistors in a mission, however the focus of this information is knowing the coloured bands which wrap across the heart of the resistor. These resistor coloration codes inform us precisely what number of Ohms of present every unit handles.
How can we learn a resistor coloration code? Why are some resistor coloration codes 4 bands and others 5 bands? What resistor do I want for an LED? We reply all of those questions and provide the instruments to rapidly calculate the right resistor for all your tasks.
Widespread Resistor Colour Codes and Their Makes use of
| Resistor Kind | 4-Band Colour Code | 5-Band Colour Code | Widespread Makes use of |
|---|---|---|---|
| 100 Ohm | Brown-Black-Brown-Gold | Brown-Black-Black-Black-Gold | LED Gentle Safety |
| 220 Ohm | Purple-Purple-Brown-Gold | Purple-Purple-Black-Black-Gold | LED Gentle Safety |
| 330 Ohm | Orange-Orange-Brown-Gold | Orange-Orange-Black-Black-Gold | LED Gentle Safety |
| 1K Ohm (1 Kiloohm) | Brown-Black-Purple-Gold | Brown-Black-Black-Brown-Gold | LED Safety, Voltage Divider |
| 4.7K Ohm | Yellow-Purple-Purple-Gold | Yellow-Purple-Black-Brown-Gold | Pull-up/down resistor for I2C |
| 10k Ohm | Brown-Black-Orange-Gold | Brown-Black-Black-Purple-Gold | Pull-up/down resistor |
| 100K Ohm | Brown-Black-Yellow-Gold | Brown-Black-Black-Orange-Gold | Bleed resistor for capacitor |
| 1 Megaohm | Brown-Black-Inexperienced-Gold | Brown-Black-Black-Yellow-Gold | Capacitive contact circuits |
Resistor Colour Code: Fast Reference
Studying Resistor Colour Codes Left to Proper
Resistors don’t have any polarity, to allow them to be utilized in any orientation in a circuit. However to determine the right resistor coloration code values we have to perceive the coloured bands on the resistor.
On a typical four-band passion stage resistor, there are three colours in a bunch. These are the primary, second important figures and the multiplier. The ultimate band is the resistor’s tolerance, a margin of error if you’ll. For almost all of hobbyists a tolerance of 5% (Gold) is ideal and customary.
We solely want the additional precision if we create delicate circuits, for instance audio and video tasks. We will all the time spot the tolerance band as it’s the solely band printed on the “shoulder” of the resistor. Search for this band to determine the orientation of the resistor.
A five-band resistor has a further band, a 3rd important determine, which affords a higher stage of accuracy ought to a mission require it. So we’ve got three important figures, a multiplier and the tolerance, which is singularly printed on the shoulder.
How you can Learn a Resistor Colour Code
Let’s use a 220 Ohm resistor, which is usually used with LED lights, for example of tips on how to learn resistor coloration codes.
- The primary important determine is purple, and utilizing the decoder we are able to see that purple has a worth of two.
- The second important determine can also be purple, so that provides us 22.
- The multiplier is brown, and this decodes to 10. If we multiply 22 by 10 we get 220.
- The ultimate band, tolerance, is gold. Gold is 5%, which suggests we are able to settle for a resistance with a 5% margin of error.
For makers requiring higher precision there are additionally 5 band resistors which have a 3rd important determine. The additional determine gives readability which will be important in circuits delicate to resistance for instance scientific and engineering devices.
Here’s a 5 band 220 Ohm resistor and its resistor coloration code.
- The primary important determine is purple, and utilizing the decoder, we are able to see that purple has a worth of two.
- The second important determine can also be purple, so that provides us 22.
- The third important determine 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 ultimate band, tolerance, is gold. Gold is 5%, which suggests we are able to settle for a resistance with a 5% margin of error.
100 Ohm Resistor Colour Code
The 100 Ohm resistor is usually used for LED safety. Finest used with white, blue and inexperienced LEDs at 5V. 100 Ohm resistors can be used with different colours however count on the brightness to vary as they aren’t the right worth.
100 Ohm resistors will be recognized through the resistor coloration code of Brown-Black-Brown-Gold and, for 5 band resistors, Brown-Black-Black-Black-Gold.
220 Ohm Resistor Colour Code
The 220 Ohm resistor is without doubt one of the most typical ones that hobbyists will come throughout, as a result of it’s usually used with LEDs. With out a 220 Ohm resistor, easy LEDs would devour an excessive amount of present and rapidly burn out. We’re utilizing the resistor to restrict the present that the LED can use. (“The sunshine that burns twice as vibrant, burns half as lengthy”). The 220 Ohm resistor will be recognized through resistor coloration codes of Purple-Purple-Brown-Gold or Purple-Purple-Black-Black-Gold.
If we had been to make use of a blue LED with a 3.2V ahead voltage (the quantity of voltage wanted to get present to move throughout a diode) and 10mA ahead present (the utmost protected present you may repeatedly move via the system with out inflicting harm) on a 5V provide we would want a 180 Ohm resistor. As an alternative we are able to use a 220 Ohm resistor, 40 Ohms increased so our LED received’t be as vibrant, however will probably be properly protected.
330 Ohm Resistor Colour Code
The 330 Ohm resistor can also be fairly frequent, being present in starter electronics kits for the Arduino and Raspberry Pi Pico. The 330 Ohm resistor can also be a viable candidate for many LEDs however some will begin to look dimmer than others. We will additionally use a 330 Ohm resistor with a buzzer to drop the tone of buzzer from “annoying” to barely much less annoying. Adafruit’s NeoPixel information recommends defending a GPIO pin by utilizing a resistor (between 300 and 500 Ohms) between the information pin enter and GPIO of your Raspberry Pi / Arduino.
A 330 Ohm resistor will be recognized through resistor coloration codes of Orange-Orange-Brown-Gold or Orange-Orange-Black-Black-Gold.
1K Ohm Resistor Colour Code
The 1K Ohm (1 Kiloohm) resistor is generally the utmost resistance used for LEDs. Any LED that makes use of a 1K resistor will probably be uninteresting, however will gentle up. The 1K Ohm resistor is usually used to effective tune a circuit or pull up/down an information pin. A 1K resistor, together with a 2.2K resistor can be utilized to kind a voltage divider that may drop 5V all the way down to round 3.4V. That is helpful when utilizing 5V elements on the Raspberry Pi’s 3.3V GPIO.
A 1K Ohm resistor will be recognized through resistor coloration codes of Brown-Black-Purple-Gold or Brown-Black-Black-Brown-Gold.
4.7K Ohm Resistor Colour Code
The 4.7K Ohm resistor is helpful for including a pull-up resistor to the SDA and SCL pins of an I2C system. Adafruit’s Stemma QT boards have this in-built, however ought to we use one other model of board, we would want so as to add a 4.7 Kiloohm resistor to each of these pins. By doing this we assure that the I2C information is accurately and persistently despatched to our system.
A 4.7K Ohm resistor will be recognized through resistor coloration codes of Yellow-Purple-Purple-Gold or Yellow-Purple-Black-Brown-Gold.
10K Ohm Resistor Colour Code
The 10K Ohm resistor is usually used as a pull-up resistor for an enter pin. For instance on Arduinos we are able to use a 10K Ohm resistor to pull-up an enter pin, in order that when the button is pressed, it pulls the enter pin excessive with 5V, triggering an motion in our code. We used a 10K Ohm resistor to pull-up the information pin on a DHT22 temperature sensor in our earlier resistor reference.
A 10K Ohm resistor will be recognized through resistor coloration codes of Brown-Black-Orange-Gold or Brown-Black-Black-Purple-Gold.
100K Ohm Resistor Colour Code
100K Ohm resistors are on the uppermost restrict of what most makers want. It is a lot of resistance in a small bundle nevertheless it has its makes use of. They’re sometimes used as bleed resistors on a capacitor, to scale back the chance of a nasty zap or to tune a delicate audio / video circuit.
A 100K Ohm resistor will be recognized utilizing the colour code of Brown-Black-Yellow-Gold or Brown-Black-Black-Orange-Gold for a 5 band resistor.
1M Ohm Resistor Colour Code
It is a lot of resistance and most hobbyists / makers won’t ever want it. We’ve used a 1M Ohm resistor with an Arduino to create a capacitive contact interface (our personal Makey Makey). However most people won’t ever want one. Nevertheless, the 1M Ohm resistor has coloration codes of Brown-Black-Inexperienced-Gold or Brown-Black-Black-Yellow-Gold.
A 1M Ohm resistor will be recognized through resistor coloration codes of Brown-Black-Inexperienced-Gold or Brown-Black-Black-Yellow-Gold.
LED Brightness Resistor Calculator
We have now a field filled with LEDs, however what are the right resistors for every coloration? To work this out we have to use a bit math and fortuitously there’s a calculation that we are able to use.
R is the resistor worth that we want for our LED and, to work that out, we have to know the provision voltage (Vs), the ahead voltage (Vf) and the ahead present (If) of the LED. We will be taught the Vf and If of an LED b referring to its datasheet. If not, here’s a desk of approximate values which can be utilized for basic hobbyist circuits.
Typical LED Ahead Voltages
| LED Colour | Vf Vary (Volts) |
|---|---|
| Purple | 1.8 – 2.1 |
| Orange / Amber | 1.9 – 2.2 |
| Yellow | 1.9 – 2.2 |
| Inexperienced | 2 – 3.1 |
| Blue | 3 – 3.7 |
| White | 3 – 3.4 |
Here’s a fast resistor and LED reference for 3.3 and 5V microcontrollers.
3.3V LED Resistor Values By Gentle Colour
| White | Purple | Blue | Yellow | Inexperienced | |
|---|---|---|---|---|---|
| Provide Voltage (Vs) | 3.3V | 3.3V | 3.3V | 3.3V | 3.3V |
| Ahead Voltage (Vf) | 3V | 2.2V | 3V | 1.8V | 3V |
| Ahead Present (If) | 20mA | 20mA | 20mA | 20mA | 20mA |
| Resistor Wanted | 150 Ohm | 55 Ohm | 150 Ohm | 75 Ohm | 150 Ohm |
5V LED Resistor Values By Gentle Colour
| White | Purple | Blue | Yellow | Inexperienced | |
|---|---|---|---|---|---|
| Provide Voltage (Vs) | 5V | 5V | 5V | 5V | 5V |
| Ahead Voltage (Vf) | 3V | 2.2V | 3V | 1.8V | 3V |
| Ahead Present (If) | 20mA | 20mA | 20mA | 20mA | 20mA |
| Resistor Wanted | 100 Ohm | 140 Ohm | 100 Ohm | 160 Ohm | 100 Ohm |
