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Calculate Resistor Values from Color Codes

The information booklet contained in many of the iBotz robots explains how many of the electrical components used to control the iBotz robots work.

One of the most widely used components is a resistor. Resistors are used to resist the flow of electricity in a circuit. The value of a resistor is given by the coloured bands on the the case of the resistor. Because it is very difficult to make large numbers of resistors with a very exact resistance value cheaply, manufacturers also give a tolerance value to let you know how close the actual value of the resistor is guaranteed to be to the value the bands saty it should be.

The coloured bands on the resistor are used to encode the resistance value and tolerance of the resistor, The first two bands describe the value, the third band a multiplier value, and the fourth band gives the tolerance.

You can use the interactive tool below to identify the resistance of the resistor, as well as its tolerance.

Illustration Copyright 1996 Danny Goodman (AE9F). All Rights Reserved.

                                Version 2.2
                 by Danny Goodman, AE9F (
                    Analyzed and described at length in 
                            JavaScript Bible
    This program is Copyright 1996, 2001 by Danny Goodman.  You may adapt
    this calculator for your Web pages, provided these opening credit
    lines (down to the lower dividing line) are in your outliner HTML document.
    You may not reprint or redistribute this code without permission from 
    the author.

There is an excellent web-based tutorial on resistance and how resisotrs work at the Molecular Expressions™ website - enter the word capacitance in to the search box, and then click on the link headed: Electricity and Magnetism: Resistance

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