Page 64 - Triwatt Custom Lead Amp Builder's Guide

Appendix 2 - How to read Resistor Color Codes

First the code

Black Brown Red Orange Yellow Green Blue Violet Gray White

0 1 2 3 4 5 6 7 8 9

How to read the Color Code

First find the tolerance band, it will typically be gold (5%) and sometimes silver
(10%).

Starting from the other end, identify the first band - write down the number
associated with that color; in this case Blue is 6.

Now 'read' the next color, here it is red so write down a '2' next to the six. (you
should have '62' so far.)

Now read the third or 'multiplier' band and write down that number of zeros.

In this example it is two so we get '6200' or '6,200'. If the 'multiplier' band is
Black (for zero) don't write any zeros down.

If the 'multiplier' band is Gold move the decimal point one to the left. If the
'multiplier' band is Silver move the decimal point two places to the left. If the
resistor has one more band past the tolerance band it is a quality band.

Read the number as the '% Failure rate per 1000 hour'. This is rated assuming full
wattage being applied to the resistors. (To get better failure rates, resistors are
typically specified to have twice the needed wattage dissipation that the circuit produces.) 1%
resistors have three bands to read digits to the left of the multiplier. They have a different
temperature coefficient in order to provide the 1% tolerance. At 1%, most error is in the
temperature coefficient - i.e. 20ppm.

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