RHEOSTAT AND STANDARD RESISTORS

RHEOSTATS AND STANDARD RESISTORS                                                 GO BACK

Rheostats are variable resistors. Its  resistance can be varied .to desire values

Standard resistors are the resistors which its resistances are known (Read about Standard Resistor Colour Codes)

The resistance of a metallic conductor is directly proportional to the length and inversely proportional to the area.

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From the above formula , to make a standard resistors or known resistors of various values, the length are measured and the Area are also measured while the resistivity is known

Example

 What length of wire will be required to make a standard resistor of resistance 0.42Ω ? the diameter of the wire is 2.0mm and

Solution

    and      

     3 meters of the wire will be required to make the standard resistors.

                      Diagram of Standard Resistor and Rheostat ( See diagram above)

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