Resistor colour code

The value of the resistor and the tolerance may be marked on the body of the component either by direct numerical indication or by using a standard colour code. The method used will depend upon the type, physical size and manufacturer s preference, but in general the larger components have values marked directly on the body and the smaller components use the standard resistor colour code. 

The actual value of a capacitor can be identified by using the colour codes given in Table 3.5 in the same way that the resistor colour code was applied to resistors. 

Small resistors are marked with a series of coloured bands, as shown in Table 3.3. These are read according to the standard colour code to determine the resistance. The bands are located on the component towards one end. If the resistor is turned so that this end is towards the left, the bands are then read from left to right. Band (a) gives the first number of the component value, band (b) the second number, band (c) the number of zeros to be added after the first two numbers and band (d) the resistor tolerance. If the bands are not clearly oriented towards one end, first identify the tolerance band and turn the resistor so that this is towards the right before commencing to read the colour code as described. 

A resistor is colour coded green, blue, brown, silver. Determine the value of the resistor. 

The next step is to test ones colour code reading capabilities. For efficient repair work, one should acquire a faultless reading capability with a rate of ten items per minute. Colour blindness inhibits the correct Identification of resistor values. This can be rather dangerous in repair work and it should be avoided by employing personnel without this deficiency. 

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