Calculate Resistance Without Calculating


Introduction: Calculate Resistance Without Calculating

About: Hey Everybody, I am very thankful to this site owner who gives us a new platform to share the things we love to make.Thanks a lot.

Have you tired of checking value of resistor every time by using a multimeter or by writing the value on resistor strip.
You would not check resistor value next time.So here it is..:)

Step 1: Let's Do It

Most resistor have 5% to 10% tolerance range.So last band is always gold(5%tolerance) or silver(10% tolerance)

Step 1:
Learn B B R O Y G B V G W

here abbreviation means
Black Brown Red Orange Yellow Green Blue Violet Gray White

You should parrot it on your fingertips.After that ,sequence these with numbers from 0 to 9 i.e.

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

Now, Here is a method.

1.Resistance Range Determination

->Look at the color of third band just before the fourth one.And follow the table below.

For the resistance value between

0.1 to 0.99 Ohm.., color of third band is always Silver.

1 to 9.9 Ohm.., Gold color is always there.

10 to 99 Ohm..,there is Black color.

100 to 990 Ohm..,Brown color.

1 to 9.9 Kilo Ohm..,Red color.

10 to 99 Kilo Ohm.., Orange color.

100 to 990 Kilo Ohm.., Yellow color is third band.

1 to 9.9 Mega Ohm..,Green Color is waiting for you.

10 to 99 Mega Ohm..,Blue color is always there.

100 to 990 Mega Ohm..,Violet color is watching at you.

1 to 9.9 Giga Ohm..,Gray Color is the third band.

10 to 99 Giga Ohm..,White color is present.

So friends after inspecting the resistance range by checking out the colors of the third band.It' time to calculate the value of remaining two bands.So here it is..

let's understood with examples:

Q.1 Color code of resistor is
White Black Brown Gold.Determine it's resistance value.

Ans. Here Third band is Brown.

->According to table if third band is Brown,then the resistance must lie between 100 to 990 Ohm.This is resistance range detection.

->Now here first band is white,so according to B B R O Y G B V G W

->White color is at last place.So the value starts with 9.

->Second band is black ,similarly it's number is 0.This is second value.
so,9 for white..,0 for black..,and brown is itself from 100 ohm to 990 ohm,so value becomes 900 Ohm.

Q.2 What is value of resistance if it's color coding is Red Red Red Gold?

Ans. Third one is Red i.e value lie between 1 to 9.9 kilo ohm.

First digit is 2,second digit is 2 acc. to bbroygbvgw.

So value can't come 22 ohm,22kilo Ohm.
It's a 2.2 kilo ohm resistor friends.

Q3. What is the color coding of 47 kilo ohm resistor?

Ans. Inspect the Resistance Range.
From table the value of resistor should be in between
10 to 99 kilo ohm,so this value lies under the range of Orange color.So the third band is Orange.

Now the number 4 should be Yellow in color and 7 should be Violet in color according to BBROYGBVGW Number coding.

So, Yellow Violet Orange is the color code,the tolerance is 5% with Gold and 10% with silver.

This method is the juice cut (opposite of short cut)of Resistance Standard calculation table.
So next time pals, the resistor should be pick up by focusing the eye only.



    • Creative Misuse Contest

      Creative Misuse Contest
    • Oil Contest

      Oil Contest
    • Water Contest

      Water Contest

    18 Discussions

    Good article but 7 is Violet you have yellow as 4 and 7. Not politically correct but we were taught (back in the day) Bad Boys Rape Our Young Girls But Violet Gives Willingly

    1 reply

    numbering of yellow color is 4 and of violet is 7 when starts from 0.Thanks

    Would still prefer the good old method:

    BB ROY Good Boy Very Good Wrestler

    1 reply

    To be honest it seems a lot of messing about. I just look at a resistor and recognise it's value immediately. Anyone with experience, either hobbyist or professional will soon memorise the pattern and have no need of a multimeter. This comes automatically without any specific learning methods.

    2 replies

    At starting , there is lot of messing,..once you have learnt it..this is common thing.

    Exactly my point except it isn't learning as such, it comes automatically through repetition without any effort to learn.

    Ah! Good one. Now please do it for five band. In particular, can you give us a system to identify which side to start with... The five band ends up with what looks like three equally spaced bands in the middle.

    1 reply

    This is applicable for four band only , i will try to figure out the problem particularly to identify the starting point.

    good info test the mind i say.

    I use a nice free app for that - or as suggested an ohm meter.

    1 reply

    Hmm,electro droid is a nice free app, the idea behind this instructable is to share this information among us ,which i got from a very talented technician.

    Seems like a lot of messing about and not all of us are Mr Memory.

    Just find the colour codes in google images, print them out and keep them with your resistors.

    1 reply

    it seems to be very messy but it is not,if you have to pick up right resistor from the bunch,just look at third band color and match with your requirement.