How to read Surface Mount resistor

To read and calculate a SMD resistor, you must find out what code the resistor is using, in order to calculate it. There are 3 categories which are shown below:

Has an R,K or M between the numbers                                                                        

To calculate a 3 digit code resistance, Find the 3 digit code on the resistor, the first and second numbers are the significant number/ first 2 digit of resistance, the 3rd digit is the multiplier. The multiplier is an exponent of 10, so on the left you see i have 131, so the first 2 digits is 1,3 and the multiplier is 1 which is 10^1. To calculate the resistance, you multiply 13 by 10^1 which is 13 x 10^1 =130 ohms. So the resistors resistance is 130 ohms.

To calculate a 4 digit code resistance, locate the 4 digit code on the resister. The first, second and third number on the resistor are the significant number/ first 3 digits of the resistance  and the 4th number is the multiplier. The multiplier is an exponent of 10 , so on the left i have a resister with a code of 4450, so the first 3 digits are 4,4,5 and the multiplier is zero which is 10^0. To calculate the resistance multiply 445 by 10^0 which is 445 x 10^0 =445 ohms. So the resistors resistance is 445 ohms.

To calculate a resistor with a Radix point. Locate the 3 or 4 digit code with an R,K or M in the middle. The letters act as a decimal, so you just replace the location of the letter with a decimal point. In this resistance code, there is no multiplier. The letters also represent the unit of the resistance in the resistor so R represents ohms, K represents kilo-ohms and M represents mega-ohms.  For example on the left i have 45R3, so you replace R with a decimal which would look like 45.3 and since R is ohms, the resistance is 45.3 ohms. Another example is 4k3 which would be 4.3k. Another example is R33 which would be .33 ohms.