RESISTANCE MEASUREMENT (COLOUR CODING)

4 – RESISTANCE MEASUREMENT (COLOUR CODING)

Aim :

1. To identify resistor value and tolerance from the colour code and multimeter reading.
2. To compare colour coded resistor value with the actual measured resistor value (by multimeter).

APPARATUS REQUIRED:

THEORY:

            Since it is not practical to print the resistance value on the resistors due to its small size, there for a method called colour code is adopted. The resistance values are generally printed on the body of bigger resistors like wire wound and metal film like resistor. But for the carbon resistor the values are colour coded since its size is very small to print. The value directly on the body of resistors. Colour coding is standardization by electronic industry association (EIA) colour bands are marked on the surface on the resistors. From one end the first band gives the first significant digit, second value gives the second significant digit of the resistance value and third band gives the multiplier and fourth band represents the tolerance in percentage value.   

PROCEDURE:

Using colour code:

1. Hold the resistor so that the colour bands are in the left end of the resistor. Write down the numeric value of the first colour band.
2. Write down the numerical value of the second colour band at the right side of the first numeric.
3. Read the numeric value of the third colour band and write down those many zeros at the right side of the second numeric.
4. Repeat the procedures for various resistors.

Using multimeter:

1. Keep the range selector switch to its suitable position shown in the multimeter load. Adjust the zero with the help of zero ohm adjuster.
2. Connect the two end of resistor to the multimeter the pointer will deflect towards the right and stop after takes the reading.
3. Compare the value with the colour code value.

CIRCUIT DIAGRAM

TABULAR COLUMN

RESULT:

      Identified the resistance value and the tolerance from the colour code, and compared it will the multi meter measurement.

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