Identification Method For Resistor Chip Resistance

SMD components have the advantages of small size, light weight, high installation density, strong seismic resistance, strong anti-interference ability, and good high-frequency characteristics, and are widely used in computers, mobile phones, electronic dictionaries, medical electronic products, camcorders, electronic kilowatt hour meters, and VCD machines. SMD components can be divided into three categories based on their shape: rectangular, cylindrical, and irregular. According to types, there are resistors, capacitors, inductors, transistors, and small integrated circuits. The nominal method for SMD components is different from that of general components. The following mainly discusses the nominal resistance method of chip resistors.
The resistance value of a chip resistor is the same as that of a general resistor, and is indicated on the resistor body. There are three methods for nominal resistance values, but the nominal method is not completely the same as that of a general resistor.
1. Digital cable position nominal method (usually used for rectangular sheet resistors)
The digital cable nominal method is to use three digits on a resistor to indicate its resistance value. Its first and second digits are significant digits, while the third digit represents the number of "0" added after the significant digit. This digit does not appear as a letter.
For example, '472' represents' 4700 Ω '; '151' represents' 150 '.
If it is a decimal, use "R" to represent the "decimal point" and occupy one significant digit, while the other two digits are significant digits.
For example, "2R4" represents "2.4 Ω"; R15 represents 0.15 Ω.
Four digit representation:
The first three digits represent significant digits, and the fourth digit represents the magnification.
2702=27000=27k Ω 
2. Color ring nominal method (usually used for cylindrical fixed resistors)
Chip resistors, like general resistors, mostly use four rings (sometimes three rings) to indicate their resistance values. The first and second rings are significant digits, and the third ring is the magnification (color ring code is shown in Table 1). For example, "brown green black" represents "15 Ω"; 'Blue gray orange silver' represents' 68k Ω 'with an error of ± 10%.
3. E96 Numeric Code and Alphabet Mixed Nomenclature Method
The numerical code and letter mixed nominal method also uses three digits to indicate the resistance value, namely "two digits plus one letter", where the two digits represent the E96 series resistance code. Please refer to Appendix 2 for details. Its third digit is the magnification represented by a letter code (as shown in Table 3). For example, "51D" represents "332 × 103; 332k Ω "; 249Y "means" 249 × 10-2; 2.49 Ω ".