Resistors and how they are rated:
Resistors are rated by wattage and ohms.
Wattage is normally determined by a resistor's size or some other markings.
The actual resistance of a resistor is a value specified on ohms.
Ohms may be determined by a color-coding scheme.
(* An ohm is the amount of resistance 1,000 feet of 10 gauge solid copper wire possesses)
Resistors are read from left to right:
The first digit starts on the left with the tolerance and some space on the right.
Use first two colors to determine the multiplicand.
The third color represents the order of magnitude of the first two numbers.
Append the number of zeros (the third color represents) to the right of the first two digits.
This yields the rated resistance (in ohms) of your resistor.
For example: YELLOW - ORANGE - RED - GOLD would yield the following:
- Yellow = 4
- Orange = 3
- Red = 2 (number of zeros to the right of the number)
- Gold = 5% tolerance
43 multiplied by 100 = 4,300 ohms (
with 5% tolerance)
Resistor Color Codes: