1. Memorize the number represented by each color of the first and second rings, which can be memorized like this: brown 1, red 2, orange 3, yellow 4, green 5, blue 6, purple 7, gray 8, white 9, black 0 .
2. Remember to keep in mind the resistance range represented by the color of the third ring, this is the key to quick understanding. specifically is:
Gold: several hours and several Ω; black: several dozen Ω; brown: several hundreds and tens of Ω; red: several hours and several kΩ;
Orange: several tens of kΩ; yellow: several hundreds of tens of kΩ; green: several times of MΩ; blue: several tens of MΩ.
From the order of magnitude, they can be divided into three major levels physically, namely: gold, black, and brown are ohm-level; red-orange' and yellow are kilo-ohms; green and blue are mega-ohms Class.
3. When the second ring is black, the color of the third ring represents an integer, that is, a few, tens, hundreds of kΩ, etc. This is a special case when reading, so pay attention to it. For example, if the third ring is red, its resistance is exactly a few kΩ.
4. Remember the error represented by the color of the fourth ring, namely: gold is 5%; silver is 10%; colorless is 20%.
Example 1: When the four color rings are yellow, orange, red, and gold in sequence, because the third ring is red and the resistance range is a few kΩ, the numbers "4" and "4" are represented by the yellow and orange colors respectively. Substituting "3", the reading is 43 kΩ. The first ring is gold to indicate an error of 5%.
Example 2: When the four color rings are brown, black, orange, and gold in sequence, because the third ring is orange and the second ring is black again, the resistance should be several tens of kΩ, according to the number represented by brown "1 "Substituted in, the reading is 10 kΩ. The fourth ring is gold, and its error is 5%.
Resistance color code identification tableColor ring resistance commonly used colors: black, brown, red, orange, yellow, green, blue, purple, gray, white (representative numbers are: 0, 1, 2, 3, 4, 5, 6, 7, 8 ,9)
Tip 1: Find the color circle that marks the error first, so as to arrange the order of the color circle.
The most commonly used colors to indicate resistance errors are: gold, silver, and brown, especially gold and silver rings. Generally, they are rarely used as the first ring of the resistance color ring. Therefore, as long as there are gold and silver rings on the resistor, It can be basically assumed that this is the last link of the color ring resistance.
Tip 2: Judging whether the brown ring is an error mark.
The brown ring is often used as an error ring, but also as a valid number ring, and often appears in the first ring and the last ring at the same time, making it difficult to identify who is the first ring. In practice, it can be judged according to the interval between the color rings: for example, for the resistance of a five-channel color ring, the interval between the fifth ring and the fourth ring is greater than the interval between the first ring and the second ring. To be wider, the order of the color circle can be determined based on this.
Tip 3: In the case that the color ring sequence cannot be determined only by the color ring spacing, the production sequence value of the resistance can also be used to determine it.
For example, the reading sequence of the color ring of a resistor is: brown, black, black, yellow, brown, its value is: 100×10000=1MΩ, the error is 1%, it belongs to the normal resistance series value, if it is read in reverse order: brown, yellow , Black, black, brown, the value is 140×1Ω=140Ω, the error is 1%. Obviously, the resistance value read according to the latter sorting is not available in the resistance production series, so the latter color wheel sequence is wrong.
Steps to quickly identify the resistance of the four-color ring resistance:first step
When we get a four-color ring resistor, first look at its fourth color ring. The fourth color ring is generally farther away from the other three color rings, so it is easy to find, and the color of the fourth color ring is also There are only two colors, gold and silver, or colorless without the fourth color ring. The reason why we need to look at the fourth color circle first is not only because of its special location and easy identification of colors, but because it will determine the colors of the first and second color circle. This important feature is determined by the nominal value. It's determined by the series.
There are three types of nominal value series, E24, E12 and E6. Their errors are ±5/%, ±10/%, and ±20/%. In the four-color ring resistance, gold and silver are used for these three colors. Respectively represent the errors of these three series, which is the fourth color circle
If it is gold, then the nominal value of the resistor is only 24 values,
If it’s silver, there are only 12 values,
If it is colorless, there are only 6 values,
Second step
After reading the fourth color circle, then look at the third color circle first. The third color circle is the key to quickly read the resistance value. Everyone knows that the third circle is multiplication. If you just read the multiplication If it is, it will affect the entire resistance reading process. We should read the multiplication directly into the unit of resistance, and add the first and second color circles to the correct result.
The above are the more commonly used colors of the third color circle, and the two colors of gray and white are generally not used because the multiplication is too large, and the color of silver is too small to be used, and there is no such color because there is no corresponding color. Multiplying, so this third color circle cannot be colorless.
third step
Then look at the first and second color rings. The first and second color rings represent the effective value. The first color ring is usually close to one end of the color ring resistance, followed by the second color ring and the first color ring. There are three color circles, and then the fourth color circle is separated by a longer distance. How to quickly read the values ​​of the first and second color circles? Please keep in mind the following mantra:
Brown, one red, two orange, three yellow, four green, five blue, six purple, seven gray, eight white, nine black, zero
the fourth step
Check whether the last read resistance value is correct
â‘ Check according to the nominal series corresponding to the color of the fourth color circle
The first and second color rings are composed of two colors of brown, red, orange, yellow, green, blue, purple, gray, white and black. According to reason, it can be matched into 1024 combinations, but we first looked at the fourth color in the first step. Ring, because the resistance values ​​of the E6 and E12 series are repeated in the E24 series, no matter whether the fourth channel is gold or silver without any of these three colors, they only have 24 corresponding resistance values, which means that the first There are only 24 color combinations of the two color circles. For example, if the first and second color circles are respectively
Brown and black, then the fourth color ring can be any of the three colors of gold and silver, because the three nominal value series have a corresponding resistance value of 1.0
Brown and brown, then the fourth color circle can only be gold, because only the E24 nominal value series has a corresponding resistance value of 1.1
Brown and red, then the fourth color circle is gold or silver, because the E24 and E12 nominal value series both have a corresponding resistance value of 1.2
Brown and yellow, then you may be dazzled, because there is no corresponding resistance value of 1.4 in the three nominal value series, you should take a closer look at this time.
â‘¡Check according to the multiplication corresponding to the color of the third color circle
Because of the multiplication of the third color ring, the resistance value of the color ring resistance is like scientific notation, so the first color ring cannot be black. Let’s illustrate the reason for this. If a four-color ring is The color circle arrangement of the resistor is black, red and gold, so the read resistance value is 20KΩ, then red, black and orange gold, the read resistance value is also 20KΩ, and the black and red gold is 02×104 in scientific notation, and Red, black, orange and gold means 20×103. Obviously the previous number is unscientific, because the first zero is meaningless, so you will notice when making the color ring resistance, if the first color ring is black. That will modify the color of the third color circle to modify the multiplication, thus ensuring that the first color circle will not be black.
â‘¢Analyze whether the resistance reading of this resistor is reasonable and correct according to the nature of the electronic product or electronic circuit.
But to be honest, with current resistance products, it is really difficult for you to distinguish the distance between the color rings. Which ring is the first ring is often identified by experience; for the four color rings, there is one more thing to learn from, then That is: the fourth ring of the four-color ring resistance is either gold or silver, but not other colors (this is not applicable in the five-color ring); so you can know which ring should be the first ring.
The first ring: Red-represents 2
The second ring: purple-represents 7
The third ring: brown-represents 1, but the "1" in the third ring is not a "significant digit", but means the number of "zero" added after the first two significant digits.
From this point of view, the resistance value of this resistor should be 270. What is the unit? In the color ring resistance, the default is "ohm" (the basic unit of resistance, the symbol is Ω).
The resistance of the above resistor is: 270Ω
So, what does the fourth ring mean? The fourth ring represents the "precision" of the resistance, that is, the error of the resistance. Gold represents an error of ±5%, and silver represents an error of ±10%. For 270Ω, an error of ±5% means that the actual minimum resistance value of this resistor is 270*(1ï¼0.05)=265.5Ω; the maximum value will not exceed 270*(1＋0.05)=283.5Ω.
When identifying the four-color ring resistance, there are two situations to pay special attention to:
1. When the third ring is black, this black ring represents the number of 0s, how many 0s? It is 0 "0", that is, "no 0", no "0" is added. Such as:
The resistance value is: 22Ω and never 220Ω!
2. Gold and silver will also appear in the third ring: as we have mentioned earlier, the fourth ring is a color ring that represents error, and two colors of gold and silver are used to indicate different accuracy; and the third ring means "add zero When the third ring appears golden or silver, how do you understand the "number of zeros added"? Just remember it like this:
The third ring-gold: move the decimal point forward by 1 place;
The third ring-silver: move the decimal point forward by 2 digits.
Give two examples:
1. Color circle arrangement: orange, gray, gold and gold
The resistance is 3.9Ω
2. Color circle arrangement: green, yellow, silver and gold
The resistance is: 0.54Ω
Because the resistance of this kind of resistance is too small, it is almost not used in general circuits, so it is actually not in the series of resistance products.
The five-color ring notation rules are as follows:
The difference between the five-color ring resistance and the four-color ring resistance is: the first three color rings are valid values, the fourth color ring is a multiplication, and the fifth color ring is an error.
Steps to quickly identify the resistance of the five-color ring resistance:â‘ The steps of identifying the resistance value of the five-color ring resistance are the same as those of the four-color ring resistance. We still look at the fifth ring first (the last ring). The last ring of the four-color ring resistance is only gold and silver without three colors. But the last ring of the five-color ring resistance has nine colors of gold, silver, brown, red, green, blue, purple and gray, which improves the error accuracy of the five-color ring.
â‘¡The second step of the five-color ring resistance identification is the same as the four-color ring resistance identification. It is also multiplied by the fourth ring (that is, the penultimate ring). Because the first three digits are valid, the five-color ring resistance is multiplied by the four-color ring. The multiplication of the ring resistance will be different. The main difference is that the multiplication of the fourth color ring is 101 times greater than that of the third color ring of the four-color ring resistance.
â‘¢The method for identifying the effective value of the first three-color ring of the five-color ring resistance is exactly the same as that of the four-color ring resistance. Because there are three effective values, the accuracy of the five-color ring resistance is significantly higher than that of the four-color ring resistance. Therefore, the five-color ring resistance is generally used as a precision resistor. Up.
The basic unit of color ring resistance is ohm, the basic unit of color ring capacitance is picofarad, and the basic unit of color ring inductance is microhenry.
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