4 Band Resistor Tolerance
Temika
I have a burned out big blueish gray resistor (probably a 1/2 or 1 watt) that I'm trying to find the value of but there is a mysterious black band at the end of the resistor where the tolerance band would be but obviously the tolerance/failure rate/temperature band cannot be black. What does it mean?
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The colored bands on a resistor can tell you everything you need to know about its value and tolerance, as long as you understand how to read them. The order in which the colors are arranged is very important, and each value of resistor has its own unique combination.
Resistor values can get to be very high in number, and there often isn't enough space to use a band for every digit. To get around this, the third band indicates that a certain number of zeros should be added after the first two digits to make up the full resistor value. In the example above, the third stripe is brown, indicating that a single zero should be added to the right of the first two digits.
If you want to go deeper into the math, this third band is officially referred to as a multiplier. The color of the band determines the power of 10 you need to multiply the first two resistor digits by. For example an orange third band with a digit value of 3 would indicate a multiplier of 103, though you can also just think of this as telling you to stick 3 zeros on the end".
The fourth color band indicates the resistor's tolerance. Tolerance is the percentage of error in the resistor's resistance, or how much more or less you can expect a resistor's actual measured resistance to be from its stated resistance. A gold tolerance band is 5% tolerance, silver is 10%, and no band at all would mean a 20% tolerance.
Some projects require your measurements to be more precise than others, and for this reason the tolerance band is useful in identifying which resistor will give you a more accurate resistance reading. The smaller the tolerance percentage is, the higher the precision in your measurements.
The following are tools to calculate the ohm value and tolerance based on resistor color codes, the total resistance of a group of resistors in parallel or in series, and the resistance of a conductor based on size and conductivity.
An electronic color code is a code that is used to specify the ratings of certain electrical components, such as the resistance in Ohms of a resistor. Electronic color codes are also used to rate capacitors, inductors, diodes, and other electronic components, but are most typically used for resistors. Only resistors are addressed by this calculator.
The color coding for resistors is an international standard that is defined in IEC 60062. The resistor color code shown in the table below involves various colors that represent significant figures, multiplier, tolerance, reliability, and temperature coefficient. Which of these the color refers to is dependent on the position of the color band on the resistor. In a typical four-band resistor, there is a spacing between the third and the fourth band to indicate how the resistor should be read (from left to right, with the lone band after the spacing being the right-most band). In the explanation below, a four-band resistor (the one specifically shown below) will be used. Other possible resistor variations will be described after.
In a typical four-band resistor, the first and second bands represent significant figures. For this example, refer to the figure above with a green, red, blue, and gold band. Using the table provided below, the green band represents the number 5, and the red band is 2.
The third, blue band, is the multiplier. Using the table, the multiplier is thus 1,000,000. This multiplier is multiplied by the significant figures determined from the previous bands, in this case 52, resulting in a value of 52,000,000 Ω, or 52 MΩ.
The fourth band is not always present, but when it is, represents tolerance. This is a percentage by which the resistor value can vary. The gold band in this example indicates a tolerance of 5%, which can be represented by the letter J. This means that the value 52 MΩ can vary by up to 5% in either direction, so the value of the resistor is 49.4 MΩ - 54.6 MΩ.
Coded components have at least three bands: two significant figure bands and a multiplier, but there are other possible variations. For example, components that are made to military specifications are typically four-band resistors that may have a fifth band that indicates the reliability of the resistor in terms of failure rate percentage per 1000 hours of service. It is also possible to have a 5th band that is the temperature coefficient, which indicates the change in resistance of the component as a function of ambient temperature in terms of ppm/K.
More commonly, there are five-band resistors that are more precise due to a third significant figure band. This shifts the position of the multiplier and tolerance band into the 4th and 5th position as compared to a typical four-band resistor.
On the most precise of resistors, a 6th band may be present. The first three bands would be the significant figure bands, the 4th the multiplier, the 5th the tolerance, and the 6th could be either reliability or temperature coefficient. There are also other possible variations, but these are some of the more common configurations.
Resistors are circuit elements that impart electrical resistance. While circuits can be highly complicated, and there are many different ways in which resistors can be arranged in a circuit, resistors in complex circuits can typically be broken down and classified as being connected in series or in parallel.
Hello! SO I'm brand new here and to electronics as well. I consider myself an intermediate programmer, and I got my arduino to enhance those skills as I'm going into computer science. Anyway for my first project I need a 220 ohm resistor. I bought one those starter kits with a uno R3. ( =oh_aui_detailpage_o02_s00?ie=UTF8&psc=1) and they all have 5 bands as opposed to 4. I googled this subject and found a band resistor calculator for 5 band resistors and I think it would be red, red, black, orange, and my guide for it doesnt have a tolerance specified (does it default to something?)
Like I said I'm kind of on my own with this I don't know anyone in real life that can help me with this, but I kind of want to do as much of it by myself as possible (at least the programming aspect of it).
Usually when resistors come in strips like your picture the value of the resistors is printed on one of the adhesive strips, in the case of your picture, 5K1, which is shortened from 5.1 K, replacing the decimal point with the K, for thousand. Strips with resistors below 1000 are usually marked with an R, like 220R. A 2.5 Ohm would be marked 2R5.
When the resistor body is blue it becomes difficult to distinguish between certain colors, such as Brown & Orange. Best to always check with an Ohmmeter, especially if the two outer bands are the same color.
That meter will probably do OK for you, although for ten dollars I would not expect outstanding accuracy. If you have a Harbor Freight store in your area, they often give away a free multi-meter sometimes just for showing up at their store. Go online to them a get a coupon.
Most multi-meters have several functions besides reading resistance: AC & DC voltage, DC current, continuity test, and diode test. If you are going to build electronic circuits a multi-meter is indispensable.
The picture you show now does appear to be 220 Ohm resistors, as indicated by the value written on the tape. They are quite common and used for limiting current to LED's, connecting external devices to your Arduino to protect inputs, and tons of other uses. Using the wrong resistor in a circuit can result in various outcomes, from nothing notable at one end to the release of the magic smoke from usually the most expensive part in your project at the other end, interspersed with weird circuit behavior and unexpected results in between..
Green-brown-black-brown I hope? (5 1 0 )
For LED current limiting, 220 or 330 ohms is frequently used in tutorials, but anything up to about 2k should work fine with modern LEDs. I usually use 1k resistors with LEDs.
The problem with metal film resistors is the blue background colour of the resistor (carbon film is beige,
metal film is blue), which shows through the colour bands making orange red and brown very hard
to distinguish in particular, particularly in artificial light. Since these three colours are commonly
used for the multiplier its easy to get the odd resistor wrong by a factor of ten.
Another issue with the blue metal film resistors is the color banding. Take a 10K 1% resistor and a 120R 1% resistor and lay them side by side. Without knowing where they came from, can you easily and reliably tell from the color bands which is which? They are both marked Brown-Red-Black-Black-Brown or Brown-Black-Black-Red-Brown. It's nearly impossible to tell which end is the tolerance band. Would have been nice if the manufacturers would make the tolerance band double wide, like that's ever going to happen.
You might want to invest in some better probes for the multimeter.
The cheap ones that come with your intended meter will most likely be a real pain in the arse to work with.
A cheap-ish pair of probes with flexible silicone cables will set you back another 15 bucks or so, but it will be so much nicer to work with!
Actually I've never seen a multimeter that was poor accuracy, they are uniformly sub-1% in my experience,
the good ones say 0.01%, which will never matter unless you are working on precision analog circuitry
(in which case you'll be using a calibration service regularly for all your test equipment!)