Resistor color codes are something that every electronics hobbyist should remember.
The old mnemonic was rather, well, disturbing, and a conscientious person would never recite it. Anyway, on with the better one! Write this down in a prominent place and you’ll have it committed to permanent memory in no time
Here’s one mnemonic “Bright Boys Rave Over Young Girls But Veto Getting Wed. Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White <=> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
Best method to memorize is – B.B. Roy of Great Britain Veto getting wed.
Alternatively, most of the colors are those from the traditional rainbow. Black is 0 (as in ‘nothing’), Brown is 1, then Red through Violet, and finally Gray and White are 8 and 9.
The multiplier band goes by the same code and can be read as “followed by N zeros”, plus Gold for “divide by 10” and Silver for “divide by 100”.
Tolerances are something of a mess: Brown and Red are 1% and 2% (you usually spot them because they have an extra significant digit), Gold and Silver are 5% and 10%, and 20% doesn’t even get a tolerance band (you will rarely, if ever, come across one of these).
To read the whole thing, put the tolerance band at your right, and go like this: “green-brown-red-gold = 5-1-00-5% = 5.1K 5%”. You’ll get used soon enough, and a bit later you’ll be spotting what you want at once. It’s also easy to classify them by decade: red is Ks, orange is 10Ks ..