Resistors are electronic devices used to reduce the current flowing in a circuit. Resistance is measured in OHMs. Resistors are identified by a colour code. The first two colour bands represent numbers, the third colour band is called the multiplier. A simple way to use this third colour band is to think of it as representing the number of 0's to be added to the first two numbers.

Many resistors have a fourth colour band, usually silver or gold. This represents the tolerance of the resistor. A gold band indicates a tolerance of + or - 5%. The gold band does not contribute to the value of the resistor.

Colour Code:

Black - 0, Brown - 1, Red - 2, Orange - 3, Yellow - 4, Green - 5, Blue - 6,Violet - 7, Grey - 8, White - 9

In the examples above, R1 has colour bands brown, black, red and gold. (brown = 1, black = 0, red = 2 and gold indicates a tolerance of 5%)

The value of R1 is 1(brown), 0(black) and 00(red) = 1000 Ohms.

R2 has colour bands green, blue, yellow and gold. (green = 5, blue = 6, yellow = 4 and gold indicates a tolerance of 5%)

The value of R2 is 5(green), 6(blue) and 0000(yellow) = 560,000 Ohms.

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