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EEE.MRCEW

E&E LAB MANUAŁ

1. BASIC ELECTRONIC COMPONENTS

1.1. COLOUR CODING OF RESISTOR

Colour Codes are used to identify the value of resistor. The numbers to the Colour are identified in the following sequence which is remembered as BBROY GREAT BRITAN VERY GOOD WIFE (BBROYGBYGW) and Uieir assignment is listed in following table.

Black	Brown	Red	O rangę	YeUow	Green	Blue	Yiolet	Grey	Wbite
0	1	2	3	4	5	6	7	8	9

Tablcl: Colour codes of resistor

i	First find the toleraiKe band. it will typically be gold (5%) and sometimes silver (10%).
	Starting from the other end. identify the first band - write down the number associated with tliat color
	Now read the next color. so write down a its vale next to the first value.
	Now read the third or 'multiplier exponent' band and write down tliat as the number of zeros.
.'nddłgt ■■	If the 'multiplier exponent' band is Gold move the decimal point one to the left. If the 'multiplier exponenf band is Silver move tlie decimal point two plac es to tlie left. If the resistor bas one morę band past tlie tolerance band it Ls aquality band.
'ikr >■ ■
	Read tlie number as tlie '% Failure ratę per 1000 hour'This is rated assuming fuli wattage being applied to tlie resistors. (To get better failure rates. resistors are typically specified to have twice tlie needed wattage dLssipation tliat tlie circuit produces). Some resistors use this band for temco information. 1% resistors have three bands to readdigits to the leftof tlie multiplier. They have adifferent temperaturęcoefficient in order to provide tlie 1 % toleraiKe. At 1% the temperaturę coefficient starts to become an important factor. at +/-200 ppm a change in temperaturę of 25 Deg C causes a value change of up to 1%

Table2: procedurę to find the value of resistor using Colour codes

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