Help reading 5-band resistor?

May 24, 2009 6 Replies

I have a resistor in an analog VOM meter that I suspect is bad. It is exclusive to the 1x ohm scale, which is now reading as if it were the



1000x ohm scale.

The color bands are as follows:



Red Grey Violet Gold Red



There is a larger space between the gold and red bands than between any other adjacent bands.



... and it is of this type:

formatting link



I read this as 280,000,000 ohms with 5% tolerance and 50 ppm temperature coefficient, but when I use a digital meter to read the resistance it comes in at 270,000 ohms.



I noticed a small hairline crack in this resistor and when I poked it with a pin a small flake of the outer coating fell off.


280,000,000 ohms seems like an awfully large value to me. Could this be a correct reading?

Thanks


287 / 10 (e.g. 28.7) at 2% tolerance.
Rich Webb Norfolk, VA

The trick I learned was bad(black 0 boys (brown 1), rape (red 2) our (orange 3), young (yellow 4), girls (green 5), but (blue 6), Violet (7) gives (grey 8), willingly (white 9).

For the tolerance bands get (gold 5%) some (silver 10%), now (none 20%).

This was long before political correctness existed and the few women in engineering had to "just live with it".

So that's 28 followed by 7 zeros, or 280,000,000.

Here's a good description

formatting link

and here's a website that decodes them for you.

formatting link

Poor me, I had to use a little cardboard thing. :-)

Either you meter is way off, you are reading it wrongly, or the resistor has really changed with age. 280m ohms is just about right.

Geoff.

Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM

I figured that was probably closer to reality so I salvaged up a 100 ohm and a 39 ohm resistor and put them in parallel to get 28 ohms and the 1x ohms scale is reading close to normal.

Thanks!

It seems the 5 and 6 band codes are different than the 4.

Here's a correct caclculator:

formatting link

Geoff.

Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM

Or this free app from Schematica.

I'm okay with the normal bands but always screw up the gold/silver multipliers -- and the tolerance bands? Fuggedaboudit.

Rich Webb Norfolk, VA

Thanks Geoff. I bookmarked it.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required