How to Read Resistor Value

A common type of resistor is shaped copper tube with two feet on the left and right. In body shape is a circle of color-coded wristbands to facilitate users recognize without measuring the magnitude of the resistance with an ohmmeter.

The color code is the manufacturing standards issued by the EIA (Electronic Industries Association) as shown in the following table. I think for a service technician knows how to read the value of the resistor is mandatory.

Immediately, the following is the resistor color table, complete with readings at each of the color bands:

How to read resistor color codes Resistor Value
Resistance read from the color of the bracelet the most forward in the direction of tolerance band is brown, red, gold or silver. Usually this tolerance color band resistor body is at most corner or also with a width that is more prominent, while the first color of the bracelet is a bit inward.

Thus the user already knows how direct tolerance of the resistor. If you have been able to determine where the first band to read next is the resistance value.

The number of circular bands on the resistor in accordance with generally greater tolerance. Usually the resistor with a tolerance of 5%, 10% or 20% have 3 bands (excluding band tolerance).

But the resistor with a tolerance of 1% or 2% (small tolerance) has 4 bracelets (not including bracelet tolerance).

The first bracelet and so on in succession shows a large value of the unit, and the latter is a factor pengalinya bracelets. For example resistor with bands of yellow, violet, red and gold. Gold bracelet is a bracelet tolerance.

Thus the sequence of color bands resitor this is the first bracelet yellow, violet colored wristbands second and third red bracelet. The fourth bracelet of course a gold-colored bracelet and this is tolerance. From table-1 is unknown if the gold-colored bracelet tolerance, this has meant resitor tolerance of 5%. Resistansisnya value calculated in accordance with the order of the color.

The first is to determine the unit value of this resistor. Because these resistors resitor 5% (which usually has three bands in addition to bracelets tolerance), then the unit value is determined by the band's first and second bands.

Still from Table-1 unknown value = 2 red bangles and bracelets green value = 5. So the first and second bracelet or yellow and violet respectively, the unit value is 25.

The third bracelet is a multiplier, and if the color orange bracelet meaning pengalinya factor is 1000. So with this unknown resistor value is the value of units x multiplier or 25 x 1000 = 25k Ohm and the tolerance is 5%. Other specifications to consider in choosing resitor on a draft of the resistance is greater than its wattage. Because the resistors working with electrified, it will be a power dissipation of heat for W = I2R watts.

The larger the physical size of a resistor can show the greater ability of the resistor power dissipation. Generally in the market available sizes 1 / 8, 1 / 4, 1, 2, 5, 10 and 20 watts. Resistor which has a power dissipation of 5, 10 and 20 watts are generally elongated rectangular-shaped cubic white, but some are cylindrical.
thank you hopefully useful

Posted in: electronic