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Resistor I.D.
Resistor Color Codes
Resistors are identified by a standard color-coding system.The colors are read from left to right.The bands are arranged to favor one side of the resister.
Resistors
The first band and the second band signify the first two digits of the ohmic value.For example 22-ohms resistor, the first two color bands are: Red and Red This signifies “2” and “2”.
The third band is called the multiplier, which is simply the number of zeroes you put after the first two digits to get the final ohmic value. If the third is brown. This means that zero will be placed after the
“22”.
Resistors
The fourth band is called the tolerance signifier.This is how much the actual value may vary from the specified value shown by the color bands.If a resistor measures more than the allowed specified value, it is considered not useable.The more expensive or the higher the construction quality, the tighter the specification.Some circuits require precision resistors to operate effectively.
Resistor Color Codes
A resistor with five bands – red, green, black,brown and brown from left to right – would be sized as follows The first three bands set the digits;
red (2) green (5) Black (0)
So the base value is 250
Resistor Color Codes
The next band is the multiplier; brown (10). So, the resistor has a value of 250 x 10, or
2500 ohms (2.5K ohms).
And , the last band is the tolerance; brown (1%). So, the resistance value is 2500 ohms + or
– 25 ohms (2.475-2.525 K ohms).
Resistor Color Codes
Some circuits require precision resistors to operate effectively.If a resistor is replaced, never use a resistor of a wider tolerance.This could cause improper operation of the circuit.
WattageResistors must be of the proper wattage value.Wattage is the amount of heat the resistor can withstand.Improperly rated components will prematurely fail.Since resistors restrict flow of electricity, electrical friction causes heat to build up within the component.The resistor must be large enough to dissipate this heat to the surrounding environment.
