Resistor is the most common element built into any electronic circuit. It can be seen everywhere: from the simplest washing machine to a modern computer. To indicate their properties, two types of markings are used: the first is the color marking of resistors by applying multi-colored rings to the case, the second is alphanumeric.
Sign designation
On the cases of resistors and capacitors of relatively significant size, their nominal resistances (capacitances) are marked using abbreviated standard designations of units of magnitude, and next to them is a probable deviation from the declared value, for example: 1.5 Ohm 10%, 33 Ohm 20%. Such values are encoded in the color marking of resistors. The encryption of the denominations of small-sized products consists of a special set of alphanumeric characters. But along with this, today a mnemonic code is widely used, that is, colored rings that make up the color marking of resistors. According to such a system, the unit of resistance Ohm is coded with the letter (E), 1000 Ohm - as (K), megaohm - narrower (M). Rated capacities of resistors from100-910 ohms are indicated in fractions of a kilo-ohm, and the range 100,000-910,000 is mega-ohms. In the case of expressing the nominal resistance as an integer, the letter designation is placed after the numbers - ZZE (33 Ohm), 1M (1 MΩ). Writing with a decimal fraction less than one puts alphabetical marks in front of the number, for example, M47 (470 kOhm). And in the case of an integer with a decimal fraction, the letter is written instead of a comma after: 1E5 (1.5 Ohm), 1M5 (1.5 MΩ). The always present tolerance is marked in the trace of the applied resistance: 5%, 10%, 15%. The color marking of the resistor can combine both types of markings.
Color coding
It consists in marking the outer shell of the device with 3 or more colored concentric stripes. Each coloring method carries a certain numerical value, revealing the properties of the resistance of the resistor. Typically, the last bar indicates the expected tolerance of the product, and the first bars indicate resistance. For example, on a marking with 4 stripes, the first two encode the size of the capacitance (Ohm), and the third serves as a multiplier for the mentioned value. The color marking of resistors can be deciphered if the product is positioned so that the wide strip and all the rings following it are closer to the left hand. Then you need to use comparative tables that help clarify the meaning of the differences.
Other standards
The color marking of imported resistors does not leave everything so unambiguous. The fact is that for domestic products their own marking is used, and for foreign ones - another. Some manufacturers even change the standards, creating their own colors. Unusual markings are used to distinguish those products that are manufactured according to MIL requirements, which differ from industrial and domestic marks, may report fire resistance properties, etc. For example, the company "PHILIPS" indicates the value of the resistors as is customary everywhere, i.e. the first digits are in ohms, and the last is the multiplier. Depending on the declared accuracy of the resistor, it is interpreted as 3-4 characters. Differences from the usual encoding lie in the meaning of the last 7, 8 and 9 digits.
