What formula is used to calculate resistance using the color code?

1 Answer
SaiGanesh Gotetti
Feb 18, 2017

There is no particular formulae but the resistance using the color codes is like #R=#[(numbers)#xx#(multiplier)#+-#(tolerance#(%)#)].

Explanation:

There are two major types of resistors: a) wire bound resistors, b) carbon resistors.
Carbon resistors are compact and inexpensive. Their values are given using a colour code.
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The resistors have a set of four (or three) co-axial coloured rings, whose significance are listed in above table. The colour are noted from left to right.
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Colour 1#-># First significant figure
Colour 2#-># Second significant figure
Colour 3#-># Decimal multiplier
Colour 4(or no colour)#-># Tolerance or possible variation in percentage.

EXAMPLE:
enter image source here
In this picture we can see a resistor of 1-orange colour, 2-red colour, 3-brown colour, 4- gold colour. now we can calculate the resistance of the resistor in the picture by using above formulae and from table i.e.,
#R=#[(numbers)#xx#(multiplier)#+-#(tolerance#(%)#)]
Orange colour#-># 3
Red colour#-># 2
Brown colour#-> 10^-1# and
Gold colour#-> 5%#
#:.# The resistance #R=(32xx10^-1 +- 5%)ohm#.

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