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Calculate the series resistor LED. (And the E12 color code.)

Here you can easily calculate the series resistor for a LED. Also for more LED’s in series. And this LED calculator automatically searches for the correct resistor in the E12 series.

LED series resistor schematic. Calculate the series resistor for a LED. Copyright © Bruno Stroobandt led resistor calculator

Calculate the series resistor LED – LED resistor calculator: Here you can easily calculate the series resistor for a LED. Also for more LED’s in series. And this LED calculator automatically searches for the correct resistor in the E12 series. NEW: This LED resistor calculator now also gives the E12 resistor colorcode (color bands code) 😎 This is also a resistor power calculator! Later in the article also: How to calculate the series resistor for a LED by hand. (formula)

Calculate the series resistance LED.  Looks for proper resistance in the E-12 series. - led resistor calculator

LED resistor calculator – LED voltage? : The voltages in the picture are for standard LED’s. Special LED’s can differ, but that is also stated on the packaging.

More info about what is an LED (Dutch , English via Google translate in the top left corner)

P.S .: I am talking about an LED resistor calculator here, but you can use this just as well if you want to, for example, have a 6-volt bicycle light lit with the 12-volt power supply of your model train power supply or a car battery, for example.

LED resistor calculator : Calculate the series resistor LED. And color code.

Fill in the fields above

and click on calculate

—(this calculator gives resistor value, color bands and the LED resistor power) —

here comes the color code

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LED resistor calculator: The Series LED resistor power: (take at least the first higher value of the calculation above) E12-Resistor power consists of 1/8 = 0.12 Watt, 1/4 = 0.25Watt, 1/2 = 0.5Watt. And higher but that does not apply here. 🙂

LED resistor calculator – WARNING: ☠️If the power is too low, there is not only a risk of failure of the resistor. But it can get so hot that you run the risk of burning yourself or even burning a fire !!!☠️

Calculate series resistor. LED long pin = positive. LED short pin = negative.

Long leg LED = positive, LED short leg = negative.

LED resistor calculator example’s : RED 1.6V LED

LED resistor for the most common cases. Such as, for example, when using an Arduino or Raspberry ™ 3.3Volt and 5 Volt. (using a 1.6Volt standard RED LED 3 or 5mm, 20 mA). These LED resistors have been calculated and the resistance has been rounded up to the first higher existing resistor in the E12 series. You will also see the color code or resistor color bands that you can find on the resistor. Only the first 3 grouped rings are important. (see later in the article)

  • LED resistor 3.3 Volt (Arduino) : 100 omh 1/8Watt (color bands resistor: brown-black-brown-silver))
  • LED resistor 4.5 Volt battery : 150 omh 1/8Watt (color bands resistor: brown-green-brown-silver))
  • LED resistor 5 Volt battery : 180 omh 1/8Watt (color bands resistor: brown-gray-brown-silver))
  • LED resistor 6 Volt battery : 220 omh 1/8Watt (color bands resistor: red-red-brown-silver))
  • LED resistor 9 Volt battery : 390 omh 1/8Watt (color bands resistor: orange-white-brown-silver))
  • LED resistor 12 Volt battery : 560 omh 1/8Watt (color bands resistor: green-blue-brown-silver))
  • LED resistor 24 Volt battery : 1200 omh 1/8Watt (color bands resistor: brown-red-red-silver))

How to calculate the series resistor LED manualy? For Your Information – formula’s.

How can you make the calculation for the LED series resistor yourself?

LED resistor calculator : manually

  1. Take the LED voltage x number of LEDs in series. (Uleds)
  2. Then take the (battery voltage) – (the total LED voltage). = Ubat-Uleds.
  3. This is the voltage that the ballast series resistor has to get rid of. (VR)
  4. Then you divide VR by the LED maximum current = R (=minimum resistor you need)
  5. And then in the E12 series you search for the first higher resistance.
  6. BUT !!! You also need to know how many watts of power this R should be.
  7. For that you do VR x LED maximum current. = P (power, power)

Calculate the Series resistor LED -E12 series.

LED resistor calculator – E12? What are e12 resistors? The E-12 series is sufficient to use as a series resistor for an LED. These have a tolerance of +/- 10%, therefore no intermediate values ​​exist. (They do exist, if this is important. For example in the E24 series, but they are more expensive !!!!)

E12 resistor, means that the values ​​between 1 and 10 are divided into 12 steps. There are also multiples of 10 of these.

E12 series resistor. are:

  • 1.0 ohm.
  • 1.2 ohms.
  • 1.5 ohms.
  • 1.8 ohms.
  • 2.2 ohms.
  • 2.7 ohms.
  • 3.3 ohms.
  • 3.9 ohms.
  • 4.7 ohms.
  • 5.6 ohms.
  • 6.8 ohms.
  • 8.2 ohms.

And after 8.2 ohms comes 10 ohms, but that is a tenfold back 1ohm.

Calculate the series resistor LED -color code E12 series.

LED resistor calculator – Color Bands? On the E12 series of resistors you see 3 colored stripes close together. And then a little further a fourth line. You have to hold the resistor in front of you so that the 3 stripes are together to your left. And then you can read the value.

The first 2 are just numbers, the third is a power of 10

There is a trick to memorize the order of colors. “Black Beetles Running Over Your Garden Bring Very Grey Weather”

  • Black = 0
  • Brown = 1
  • Red = 2
  • Orange = 3
  • Yellow = 4
  • Green = 5
  • Blue = 6
  • Violet = 7
  • Gray = 8
  • White = 9
LED ballast series resistor. 1000 ohm = brown - black - red
LED resistor calculator – color bands

Example. Brown-Black-Red = “1”, “0 ″ and that x “ 10 to the second power” => 10 × 100 = 1000 ohms or 1k (ilo) ohms = or short: 1k.

Example 2. Yellow-Violet-Orange = “4”, ”7 ″ x 10³ => 47 × 1000 = 47k.

If the third ring = gold. Then its just the first 2 numbers / 10. (yellow-violet-gold = 4.7 ohm)

If the third ring is silver. Then its the first 2 numbers / 100. (yellow-violet-silver = 0.47 ohm)

P.S.: The fourth ring gives the tolerance. (accuracy) Silver = 10% and Gold = 5%. And there are even more precise resistances. But a) they are more expensive, and b) this is necessary, for example, to make a radio transmitter, but not as a simple series resistor.

(At E24 and better you have a dash more as a number. So 3 numbers, the fourth is the power and at the back (right) you also have red = 2% tolerance and brown = 1% tolerance)

DIY electronics – fun

This is the end of ‘the LED resistor calculator’ Here is a simple DIY project: How to turn 1 LED on and the second LED off with one electronic switch? 2 LED control display. (Can be used for model-train projects)

The End ‘Calculate the series resistor LED – Easy and automatic search in E12 sersies’.

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