How to read Resistor Color Codes

First the code

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

The mnemonic

Bad Boys Ravish Only Young Girls But Violet Gives Willingly PC_fascists

Black is also easy to remember as zero because of the nothingness common to both.

(Please don't add or change the mnemonic - it will only get reverted -admin)

How to read the code

First find the tolerance 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 that color; in this case Blue is 6. Now 'read' the next color, here it is red so write down a '2' next to the six. (you should have '62' so far.) Now read the third or 'multiplier exponent' band and write down that as the number of zeros. In this example it is two so we get '6200' or '6,200'. If the 'multiplier exponent' band is Black (for zero) don't write any zeros down. If the 'multiplier exponent' band is Gold move the decimal point one to the left. If the 'multiplier exponent' band is Silver move the decimal point two places to the left. If the resistor has one more band past the tolerance band it is a quality band. Read the number as the '% Failure rate per 1000 hour' This is rated assuming full wattage being applied to the resistors. (To get better failure rates, resistors are typically specified to have twice the needed wattage dissipation that the circuit produces). Some resistors use this band for temco information. 1% resistors have three bands to read digits to the left of the multiplier. They have a different temperature coefficient in order to provide the 1% tolerance. At 1% the temperature coefficient starts to become an important factor. at +/-200 ppm a change in temperature of 25 Deg C causes a value change of up to 1%

BS 1852 Coding for resistor values

BS 1852(British Standard 1852). The letter R is used for Ohms and K for Kohms M for Megohms and placed where the decimal point would go.

At the end is a letter that represents tolerance Where M=20%, K=10%, J=5%, G=2%, and F=1% D=.5% C=.25 B=.1%

BS 1852 coding examples
R33	0.33 ohms
2R2	2.2 ohms
470R	470 Ohms
1K2	1.2K ohms
22K	22K ohms
22K2	22.2K ohms
4M7	4.7M ohms
5K6G	5.6K ohms 2%
33KK	33k Ohms 10%
47K3F	47.3 K Ohms 1%

Common surface mount coding

The third or forth digit is the multiplier

Thus 103 is a 10K resistor

475 is a 4.7M resistor

Measure resistors with Volt Ohm meter.

We now have a program that calculates the minimum error on resistor dividers of up to 4 values.