Is there a rhyme for remembering colour bands on a resistor?

Answer 1

A useful mnemonic matches the first letter of the color code, by order of increasing magnitude. There are many variations:

• Boys better remember our young girls become very good wives.. BYU Engineering Department

• Bad boys rape our young girls behind victory garden walls.
• Bad boys run our young girls behind victory garden walls.
• Bad boys rape our young girls but Violet gives willingly.
• Big boys race our young girls but Violet generally wins.

The tolerance codes, gold, silver, and none, are not usually included in the mnemonics; one extension that includes them is:

• Bad beer rots our young guts but vodka goes well - get some now.

Since B can stand for both "black" and "brown", variations are formed such as "Blackboys rape our young girls...".

Humorous, offensive, or sexual mnemonics are more, but these variations are often considered inappropriate for classrooms, and have been implicated as a sign of sexism in science and engineering classes. Dr. Latanya Sweeney, associate professor of computer science at Carnegie Mellon, a black woman, mentions the mnemonic ("black boys rape only young girls but Violet gives willingly") as one of the reasons she felt alienated and eventually dropped out of MIT in the 1980s to form her own software company.

A politically-correct mnemonic that has attained some traction in recent years is:

• Big brown rabbits often yield great big vocal groans when gingerly slapped.

Another mnemonic that is not offensive and can be used in the classroom is:

• B. B. ROY of Great Britain has Very Good Wife.

Other mnemonics commonly taught in UK engineering courses include:

• Bye Bye Rosie Off You Go Birmingham Via Great Western
• Bye Bye Rosie Off You Go Bristol Via Great Western
• Bye Bye Rosie Off You Go But Via Great Western
• Bye Bye Rosie Off You Go do Become a Very Good Wife
• Bill Brown Realized Only Yesterday Good Boys Value Good Work

The colors are sorted in the order of the visible light spectrum: red (2), orange (3), yellow (4), green (5), blue (6), violet (7). Black (0) has no energy, brown (1) has a little more, white (9) has everything and grey (8) is like white, but less intense.