Resistor identification

[Geoffreybombom]

Is gold/silver/red/red 2.2 ohms or .22 ohms? Thank you.

 

[cj66]

That'll be red/red/silver/gold @ 0.22 5%.

Colours can be misleading under different light sources so I'd measure it with a DMM before using.

 

[stevec67]

Is gold/silver/red/red 2.2 ohms or .22 ohms? Thank you.

0.22. It's 22 x 10-2.
There's a chart on the net of course, I knew the 22 bit but not the multiplier. As you may know you read the bands the other way.

 

[bugbear]

I find magnification (either a simple lens, or a camera on "macro") can be helpful. Wiping the dust off is also good!

 

[chiily]

Always useful

https://www.digikey.co.uk/en/resour...ors/conversion-calculator-resistor-color-code

 

[Geoffreybombom]

So which is it? 2.2 or .22. Cheers.

 

[Barrymagrec]

#2.

 

[Geoffreybombom]

Anybody?

 

[Barrymagrec]

#2.

 

[Richard Lines]

That'll be red/red/silver/gold @ 0.22 5%.

You've already had your query answered in the second post 0.22R ±5%

Regards

Richard

 

[Geoffreybombom]

Ok, thanks to everyone.

 

[davidsrsb]

Red Red Silver Gold
Is 22 x 0.01 @ 5%
So 0.22 Ohm 5%
Precision in sub Ohm values is expensive

Red Red Gold Silver would be
22 x 0.1 !0%
2.2 Ohm

edit: corrected multiplier swap

 

[Richard Lines]

David,

The Silver band is a 0.01 multiplier not 0.1.

Regards

Richard

 

[cj66]

Thus..

 

[Geoffreybombom]

Thanks to everyone who helped

 

[colasblue]

What's this resistor actually for?

The only place you'd normally see 0.22R is in the output stage of a class AB power amp, and the resistors in such applications are often wirewound and have printed values rather than colour bar codes.

If grey has been misread as silver it's 2.2G which is a pretty implausible value for any application but if it's actually white it's 22R.

Colours can fade over time and are altered by heat which sometimes makes identification challenging.

 

[Geoffreybombom]

Thanks, it’s one of 4 resistors listed in Roberts guide to the A&RA60 , I have asked him the values but he has not replied yet. I have the service manual and that says r22, but I’m not the sharpest tool in the box so I thought I would ask on here. I have an eye glass and they are definitely red red silver gold. Cheers.

 

[colasblue]

That will definitely be 0.22R then.

In his thread he replaced them with green coloured Welwyn wirewounds, which have printed values (Fig 5).

The "before" picture is fig1 and yes the originals are actually colour coded composition resistors.

Note in this application the wattage is important and your replacements need to be rated to at least 2W.

 

[a.palfreyman]

Generally the position of the 'R' dictates the position of the decimal point:
22R = 22 ohm
2R2 = 2.2 ohm
R22 = 0.22 ohm

 

[Geoffreybombom]

Thanks to you all for helping, I have learnt some things today