How is the marking of the resistors color-coded?

A resistor is one of the main elements of an electrical circuit that has a constant or variable resistance and serves to convert an electric current into a voltage (and vice versa), absorb electricity and perform a number of other operations. This passive element is an integral part of any device. Therefore, you consider yourself an experienced electrician or just a fan of electronics, you will find it useful to mark the resistors with colored strips, and alphanumeric designations to compare the characteristics of different components.

Designation of resistors on circuits

In the schematic diagrams of electrical devices, the resistor is designated as a rectangle, on top of which the letter R of the Latin alphabet is put. Following the symbol is the serial number by which the element can be found in the specification. The circuit designation ends with a set of numbers that indicate the nominal resistance. So, the inscription R12 100 will mean that a 12-ohm resistor is set to 100 ohms.

An important characteristic of the elements is their power. Ignoring this parameter, you risk disabling the whole circuit, even if the determination of the marking of the resistors was performed correctly. On the diagrams it is denoted:

• Roman numerals ranging from 1 to 5 watts;
• Horizontal band at a value of 0.5 W;
• One or two inclined lines at a power of 0.25 and 0.125 W respectively.

After the serial number of some resistors, a "*" sign may appear. It means that the characteristics given are only approximate. The exact values you will need to choose yourself.

Alphanumeric designation

The alphanumeric marking is characteristic for elements of Soviet manufacture, as well as some world-class products. The marking of imported resistors and domestic products can start with both a digit and a symbol. The units of measurement are denoted as follows:

• The symbol "E" or "R" indicates that the denomination is expressed in ohms;
• The letter "M" informs us that resistance is expressed in megaohms;
• The "K" sign is supplemented with all the numerical values expressed in kilograms.

If the character stands after the numbers, then all values are expressed in integer units (33E = 33 ohms). To denote the fraction of the letter put in front of the numbers (K55 = 0.55 kilo = 550 ohms). If the sign separates the numbers, then the resistivity is expressed in integer values with a fractional part (1M3 = 1.3 megaohm).

Denomination of the denomination by color

The length of some "resistances" is only a few millimeters. To put and consider the letters and numbers on this element is impossible. To compare these components, the labeling of resistors with colored strips is used. The first two bands are always responsible for the nominal. Other strips of the account have a certain value:

• In the 3- or 4-band markings, the third dash determines the multiplier, and the fourth determines the accuracy;
• In 5-band designations, the third color indicates the nominal value, the fourth color indicates the multiplier, and the fifth color indicates the precision;
• The sixth bar indicates the temperature coefficient of resistance or the reliability of the element, if it is thicker than the others.

The color of the bars indicates the numeric values assigned to them. To understand this, the table of marking of resistors will help, where to each shade there corresponds a certain multiplier, or a digit. For example, we have a resistor with a red, green, brown and blue stripes. Having deciphered the values, we learn that before us a resistor of 25 * 10 Ohm = 250 Ohm accuracy of 25%.

Sequence of strips

How to determine which side to begin decryption? After marking the resistors with colored strips can be deciphered in both directions. In order not to get confused, you should remember a few simple rules:

1. If there are only three bands, the first will always be located closer to the edge than the latter.
2. In 4-band elements, the direction of reading should be determined by silver or gold color - they will always be located closer to the end.
3. In other cases, it is necessary to read so that the value from the nominal series is obtained. If it does not work, it's worth deciphering from the other side.

A separate case is the location of one black jumper on the body. It means that the element has no resistance and is used as a jumper. Now you know how to read the marking of resistors with colored strips, and you will not have any problems with determining the nominal value of the element.