Color designation for 5 band resistors. Three-character marking EIA96. How to determine the resistance of a resistor by color

Resistors are elements electrical circuit having their own resistance. In practice, a rare scheme can do without their use. Resistors are classified by accuracy class, power, nominal resistance and other parameters.

Description

Resistors are very small in size, a few millimeters, which greatly complicates the placement of a readable marking. For this reason, an international color coding system for electrical components has been adopted. According to generally accepted requirements, markings should be located on the body of permanent resistors in the form of multi-colored stripes or rings. This designation method ensures ease of reading in any direction. The starting marking strip is located closest to the edge of the element. In situations where housing features or other reasons make it difficult to mark in this way, the first ring is indicated by a line twice as wide.

The marking should be read from the leftmost lane to the right. If it cannot be found, the resistance corresponding to the standard nominal series is taken as true (that is, we read the other way around if this does not work).

Rating table

The color marking and reading of resistors is based on a universal table of nominal values ​​and the corresponding colors.

It is called universal because it can be used equally effectively to read not only the denomination, but also the multiplier (decimal indicator). Digital values-2 and -1 are assigned for convenience of working with decimal powers.

Standard marking

Any type of permanent resistor is color-coded with 3 to 6 color stripes. Let's look at everything below possible options rings

With 3 rings

This system is used with respect to constant resistors, characterized by a permissible deviation within ±20% (nominal series E6, that is, for each multiplier there are only six different meanings resistance values). The colors have meanings corresponding to the main table. The first two bars mark the resistance, and the last one is the decimal value.



According to the scheme for calculating the resistor resistance, the formula is used: R = (10D1 + D2)*10^E. Looking at the table, we see that the resistance value of the resistor from the figure (Red, Red, Green) is R = (20+2)*10^5 = 2200000 = 2.2MOm ±20%.

With 4 rings

This color coding of resistors is intended for elements from the nominal series E24 (5%) and E12 (10%). In this system, the first two bars represent the resistance, and the next one represents the decimal factor. The fourth strip shows the resistance tolerance: gold - ±5%, silver - ±10%.

Formula for calculating resistance: R = (10D1 + D2)*10^E ± S. Thus, for the resistor shown in the figure (Green, Brown, Red, Gold) R = (10*5 + 1)*10^2 = 5100 will be equal to 5.1KOm ±5%.

With 5 rings

This marking system is designed to identify resistors with tolerances up to 5%. The reading principle is the same: the first three lines indicate the denomination, and the fourth and fifth lines indicate the decimal factor and tolerance.

Formula corresponding to this system. Formula: R=(100D1+10D2+D3)*10^E ± S.

For resistors in the E48, E96 and E192 rating series, an additional precision resistor table is used.

Thus, the resistance value of the resistor shown in the figure (Red, Blue, Blue, Brown, Green) is R = (200+60+6)*10 = 2660 = 2.66 KOm ±0.5%.

With 6 rings

In addition to the listed indicators, colored stripes can also indicate the temperature coefficient of resistance. This indicator shows the greatest change in the resistance of the resistor when heated or cooled by 1˚C. Its value in the marking is measured in millionths of the nominal value per degree - ppm/OC. The correspondence between the temperature coefficient and colors is presented in the table:

The picture below shows a 6-band color coded resistor. In this case, each ring has the same purpose as in the example with 5-band markings. The last band is used to indicate the TCR value.



R = (100D1 + 10D2 + D3)*10^E ± S (Appm/˚C)

After decoding from the available tables, we obtain the following value of the resistor resistance:

R = (500+7+2)*10 = 5.72 KOm ± 1% (10 ppm/˚C)

Sometimes the sixth ring is used to indicate the reliability of the resistor when its width is at least 1.5 times larger than all the others. This indicator is measured as a percentage and means the number of element failures per 1000 working hours. Reliability standards are also indicated by color rings, according to the following table:

General table

If necessary constant use listed tables, it is much more convenient to have a summary table of the correspondence between colors and denomination indicators, decimal multiplier, tolerances and temperature coefficient. (For some reason, the tolerance value changes inconsistently - 1, 2, 0.5, 0.25,0.1, 0.05)

The marking rules specified here correspond to almost all non-wireless resistors with flexible leads.

Wirewound resistors

The requirements for color marking of wirewound resistors are not much different from the above requirements for their counterparts of other types. However there are a few differences:

• the wide white stripe located at the beginning does not indicate the nominal value, but indicates a wirewound type of resistor;
• for marking wire parts, decimal factors higher than the 4th power are not used;
• the colored stripe at the end of the marking sometimes indicates the properties (for example, heat resistance or fire resistance) of the resistor, rather than the TCR value.

In addition, wirewound resistors differ slightly in their tolerances. The following general table shows the tolerances and color values ​​for wirewound resistors.

It is worth noting that some manufacturers of imported resistors adhere to their own color marking system. For example, with Phillips, in addition to the color of the stripes, the color of the body, as well as the location of the stripes relative to each other, matters. These features may indicate the properties and manufacturing technology of the element. Panasonic and CGW, in addition to color ones, use leading and trailing rings for marking distinctive properties element and technology.

Other marking systems

On old Soviet resistors, a different, simpler marking was used - the resistance indicator was simply written on them. Letters of the Latin alphabet were used to indicate the decimal power of numbers. R – first degree, K – third (thousands), M – fourth (millions). For example, digital marking 2M5 means that the resistor value is 2500 KOm, and 1K7 - 1700 Ohm. This method is very simple and allows you to instantly calculate the resistance without using additional tables. The only drawback could be fixing the resistor on the board in such a position that the inscription was at the bottom and it became impossible to read. This became a significant problem when it was necessary to save space on the board, as, for example, in Japanese technology those years. Therefore, such a labeling system has not taken root in other countries of the world.

With development electronic technologies It became impossible to solder resistors to the boards through special holes. This took up too much space, and the general trend of miniaturization of equipment dictated its conditions. This is how a new method of mounting microboards appeared - SMD (surface mount technology), where circuit elements are soldered to the track itself without legs or holes. To mark resistors, diodes, capacitors, and other components of microboards and chips, a new system had to be defined.

Marking SMD resistor ov is partly similar to the Soviet method - symbolic and alphabetic notations are also used here, but, of course, with their own arrangement rules. Here, for example, a letter is not always required, and R is used as a separating comma in some situations. SMD encoding is divided into three types:

• Codes with 3 digits. The first 2 indicate the nominal value in Ohms, and the last is the decimal power of the number (“182” will mean 18*100 = 1800 Ohm).
• Codes with 4 digits. Here the resistance is indicated in the same way as in the 3-digit marking, but with 3 digits indicating the value (“4502” means 450*100=45 KOm).
• 3 character codes. In these codes, the first two digits indicate the denomination, and the next letter indicates the number of zeros (decimal power). The following symbols are used: F = 10^5, E = 10^4, D = 10^3, C = 10^2, B = 10, R=10^-1, S=10^-2. For example, an SMD resistor marked 14D has a nominal value of 14 KOm.

In accordance with GOST 28883-90 and international standard, the resistance of the resistors is marked in the form of colored rings. Each colored ring corresponds to a specific digital code. Markings with three stripes are used for resistors with an accuracy of 20%, with four stripes - with an accuracy of 5% and 10%, with five - with an accuracy of up to 0.005%. The sixth strip on the resistor shows the temperature coefficient of resistance (TCR). Color coding on resistors shifted to one of the pins and read from left to right. The first stripe is the one closest to the resistor terminal. If, due to the small size of the resistor, the color marking cannot be moved to one of the terminals, then the first sign is made in a strip with a width approximately twice as wide as the others. Color coding resistors from foreign manufacturers, which are most widespread in our country, most often consist of four color rings. The resistance of the resistor is determined by the first three rings. The first two rings are numbers, and the third ring is the multiplier. The fourth ring represents the permissible deviation of the resistor's resistance from its nominal value.

Color coding of 3-band resistors.

The color of the first two stripes indicates the first digits of the resistance. The third line means a multiplier in the form of a power of ten, by which you need to multiply a number consisting of the first two digits. The accuracy of resistors with 3 bands is 20%.

The resistance of a three-band resistor can be found using the formula:

Color coding of 4-band resistors.

The color of the first two stripes indicates the first digits of the resistance. The third line means a multiplier in the form of a power of ten, by which you need to multiply a number consisting of the first two digits. The fourth bar indicates the percentage accuracy of the resistor. It can be silver or golden in color, which means a tolerance of 10% or 5%, respectively.

The resistance of a four-band resistor can be found using the formula:

where R is the resistor resistance, Ohm; A - color number of the first stripe; B - color number of the second stripe; C - color number of the third stripe.

Color coding of 5 band resistors.

The color of the first three stripes indicates the resistance numbers. The fourth line means a multiplier in the form of a power of ten, by which you need to multiply a number consisting of the first three digits. The fifth bar indicates the accuracy of the resistor in percentage.

The resistance of a five-band resistor can be found using the formula:

R=(100A+10B+C)10 D ,

where R is the resistor resistance, Ohm; A - color number of the first stripe; B - color number of the second stripe; C - color number of the third stripe; D - color number of the fourth stripe.

Color coding of 6 band resistors.

The color of the first three stripes indicates the resistance numbers. The fourth line means a multiplier in the form of a power of ten, by which you need to multiply a number consisting of the first three digits. The fifth bar indicates the accuracy of the resistor in percentage. The sixth band indicates the temperature coefficient of resistance.

Resistors are the most common elements in electronic technology, the main parameters of which are:

• nominal resistance;
• rated power dissipation: the maximum number of watts generated by the resistor as heat during operation;
• permissible deviation of resistance from the nominal value, expressed as a percentage;
• temperature coefficient: change in element resistance with a temperature change of 1°C, expressed as a percentage.

New manufacturing technologies lead to smaller sizes electronic components. And if earlier the designations of resistors were alphanumeric, now for ease of reading they began to use markings with colored stripes.

Resistor color coding scheme

The color marking of resistors consists of three to six stripes, but in terms of power they are distinguished by other characteristics. The first stripe is the one closest to the edge. If the dimensions of the part do not allow this shift to be clearly expressed, then the first strip is made twice as wide as the others.

The number of stripes depends on the permissible error. The smaller the tolerance, the more numbers are required to record the characteristics of the component. There are two types of color marking for resistors.

• Designation with 3-4 stripes. In this case, the first two stripes are the mantissa, the third is the multiplier, and the fourth is the error tolerance in percentage.
• Designation with 5-6 stripes. The first three stripes are the mantissa, the fourth is the multiplier, the fifth is the tolerance, the sixth is the temperature coefficient of resistance.

Each of the colors accepted for designation is assigned either a mantissa, or a multiplier, or any characteristic value. They can be determined from the resistor marking table.

Sometimes difficulties arise in determining the beginning of the marking of miniature resistors. In this case, the developers have provided a little trick: the code cannot begin with a silver, gold and black stripe. But most elements always have one of them at the end.

If you can’t determine the beginning at all, you can measure the resistance of the element with a multimeter and estimate its order. Then compose two versions of the code at both ends and compare them with the measured value. Only one option will do.

Dissipation powers are determined either by the dimensions or by the type indicated on the housing. On circuit diagrams power 0.125 W corresponds to two slashes inside the element, 0.25 W - one slash, 0.5 W - horizontal. Other values ​​are indicated in Roman numerals.

People who do renovations household appliances, remember the inconvenient Soviet resistors, the capacity of which was often very difficult to determine without desoldering it from the board. This situation arose because the capacity was printed in the form of numbers on only one side of the device and it was not always possible to see them. Subsequently came into useColored circular stripes were applied to the body, which are visible in any position of the element. Let's look at how to correctly determine the value of permanent resistors using strips.

A resistor is electronic device, which has a certain resistance. Its main task is to convert current into voltage and vice versa. Due to its small size, it is not always possible to apply and read markings from a resistor - for example, a 0.25-watt device, quite often used in systems engineering, has a length of no more than 3.2 mm with a diameter of 1.8 mm. That is why it was developed color scheme markings. It is international and has been approved by the IEC (International Electrotechnical Commission) andrequirements of GOST 175-72.

Marking resistors with stripes

Color Chart

To read resistor markings with colored stripes you can use this table:

The last numbers are used for the decimal multiplier. It should also be remembered that there are six accuracy levels provided by GOST. For the E6 series, a deviation of 20% is allowed, for E12 - 10%, E24 - 5%, E48 - 2%, E96 - 1%, E 192 - 0.5%.

Labeling rules

Classical consists of 3-6 stripes/rings. The more stripes, the greater the measurement accuracy. Let's look at the most popular options.

Devices with three stripes

Such marking is used only for those elements that have “planned” deviations of no more than 20%. The numbers related to colors can be taken from the table above. The first and second circles show the resistance of the device, the third - the multiplier indicator.

If we designate the first strip D1, the second D2, the third E, then the formula for calculating the resistance will look like this:

R=(10D1+D2)*10E

For example, on the resistor you are looking for, the first stripe is red, the second is green, and the third is yellow. We are looking for resistance (10*2+5)*104=25*10 to the 4th power=250000 Ohm or 250 kOhm.

Devices with 4 stripes

Used for devices with an accuracy of up to 5-10% (series E12 and E24 according to GOST marking). Resistance marking scheme by color remains the same: the first two rings are the resistance value, the third is the decimal multiplier, the fourth is the tolerance. Golden tolerance - 5% (applies to the E24 series), silver - 10% (E 12 series). In this case, the formula looks like this: R=(10D1+D2)*10E±S, where the first stripe is D1, the second is D2, the third is E, the fourth is S.

Example:if you see a device with 4 stripes of green, orange, red and gold, then the resistance will be equal toR=(50+3)*10 second degree=5300 Ohm+-5% or 5.3 kOhm ± 5%.

Devices with 5 stripes

Similar marking of resistors by stripes used for strips E48 - 2%, E96 - 1%, E 192 - 0.5%. The technique for counting the first three bars remains the same, the fourth indicates the decimal multiplier, the fifth indicates the tolerance level. The formula is as follows: R=(100D1+10D2+D3)*10E±S, where D1, D2 and D3 are the first three circles, E is the fourth, S is the fifth. Tolerances are indicated as follows:

• E48 (2%) - red;
• E96 (1%) - brown;
• E192 (0.5%) - green;
• 0.25% - blue;
• 0.1% - purple;
• 0.05% - gray.

Six-band devices

Professional repairmen know that some resistors have a so-called temperature resistance coefficient, or TCR for short. This parameter shows by what amount the resistance of the element increases/decreases when the temperature changes by 1 degree. This coefficient is measured in ppm/ O C (parts per million or millionth of the available denomination, divided by the number of degrees). Let's look at the designation of resistors by color on the sixth ring:

1. Brown color - 100 ppm/ O C.
2. Red - 50 ppm/ O C.
3. Yellow - 25 ppm/ O C.
4. Orange - 15 ppm/ O C.
5. Blue - 10 ppm/ O C.
6. Violet - 5 ppm/ O C.
7. White - 1 ppm/ O C.

Let's look at an example of determining a resistor by color marking efor 6 rings. For example, we have a resistor with red, green, purple, yellow, brown and orange stripes. The resistance will be equal to (100*2+10*5+7)*10 4 +-1% (15ppm/ O C) or 2570000±1% (15ppm/ O C) or 2.57 ±1% (15ppm/ O C) MOhm.

Attention:the sixth ring is often used to calculate the element's reliability factor. If it is of standard width, then it determines the ppm/ coefficient O C, if it is one and a half times wider, then it shows the percentage of element failures per thousand hours of operation.

The color designations in this case are as follows:

1. Brown color - up to 1 percent failure rate.
2. Red color - no more than 0.1% failures.
3. Orange color - no more than 0.01% failure rate.
4. Yellow - no more than 0.001% failures per 1000 hours of operation.

The following option can be used as a worksheet to determine resistance:

Wirewound resistors

For wirewound resistors, slightly different decoding resistors by color . In any case, the first stripe will be wide white stripe, which talks about manufacturing technology (wire). They cannot have more than 4 stripes; the last ring indicates the properties of the microelement. Study our table - it will allow you to understand how to correctly read the ratings of wire devices.

As you can see, there is nothing complicated about the markings - using our two tables you can easily determine the capacity of any denomination. A little practice and you will remember the key colors, since resistors are mostly made of limit values are used quite rarely. An experienced technician immediately reads the markings and understands how the device works.

Below is a program for determining the resistance value of a resistor and its accuracy using the color markings on the resistor body. To correctly set the marking, a number of conditions must be met:

The outermost ring on the resistor body indicates accuracy, select the appropriate color in the rightmost form

To indicate the color of other rings, also use the appropriate forms

ATTENTION!!! The program is designed only for marking with 4 and 5 rings!!!

If you need to find out the marking for a 4-ring designation, then in the first form on the left, select the value - "there is no band".

Coded designation of nominal resistance, tolerance and designation examples

The code marking of resistors consists of three or four characters: two numbers and a letter or three numbers and a letter. The code letter is a multiplier indicating the resistance in Ohms and determines the position of the decimal point. The code designation of the permissible deviation consists of a letter of the Latin alphabet.

An example of a resistor code marking: code 3R9J - consists of four characters, the letter R in this case is something like a separating comma, i.e. we get the number 3.9. The last letter indicates, according to the table, a tolerance of 5%, as a result we get a resistor of 3.9 Ohm +-%5.
Let's look at another example: code 12K4F - consists of 5 characters, the numbers form the resistance value, the letter K is a separator and a multiplier at the same time, focusing on the table we get 12.4 103 Ohms, the letter F indicates an accuracy of +-1%, in As a result, we get 12.4 kOhm±1%

Color marking of nominal resistance and tolerance of domestic resistors.

Color marking of resistors is indicated by 3 or more colored stripes on the resistor body. Each color shapes numeric value resistor resistance, according to the table below. As a rule, the last strip indicates the tolerance value of the resistor, and the first stripes form the resistance value, for example, for four-band markings, the first two stripes indicate the resistance value in Ohms, and the third strip is a multiplier for this value.

Code marking of domestic resistors

According to GOST 11076-69 and the requirements of Publications 62 and 115-2 IEC in the code marking, the first 3 or 4 characters indicate the value of the nominal resistance of the resistor, which is determined by the base value from the EZ...E192 series, and the multiplier. The symbol at the end of the code indicates the tolerance class of the resistor. The requirements of this GOST and IEC practically coincide with the foreign standard BS1852 (British Standard).

It should be added that often on the resistor body, in addition to the main code, a code is added that carries information about the type of resistor, its rated power, etc.