Everyones favorite, maplin resistors ;-)

[jimangus]

Just bought some maplin metal film resistors because it is easy, no credit card or minimum order nonsence. They are the 2watt 1% metal films.

However measuring them on my DMM they measure 99.2k instead of 100k. All the other resistors i have bought measure exact so its not the DMM, the question is are they just rubbish or will they toe the line with a voltage across them ?

the colour coding is odd too it is brown, black, black, orange, brown. nearest i can see to that (ignoring one of the blacks ) is 10k.

What is going on, i need to ask as i have an inherent mistrust of maplin resitors due to them at one point sending me the incorrect value and it toasting in my amp, i now allways check them whenever i buy them.

Thanks in advance for any help on this very dull conundrum.

[NickG]

Well 99.2k is less that 1% from the target value, as long as they are more that .5% tol then thats fine. What more do you want for a few pence :-)

As for the codes, its just using four bands for the value instead of three, so its 1 (brown), 0, (black), 0 (black), 10^3 (orange).

So thats 100,000 or 100k.

(EDIT - wrote this at the same time as Nick's post above, but included a pretty picture!)

Errm,

1% of 100k is 1k, so at just 0.8k down they are within tolerance.

For a five band resistor the colour code is correct (i.e. 100k 1%), the first three are the digits (1, 0, 0), the fourth is the multiplier (x1000) and the fifth is the tolerance (+/- 1%):


Where's the conundrum?

[Richard]

Yes, it's not so long ago that 20% tolerance was normal, 10% was high quality and "high stability" 5% were expensive and reserved for special apps!

The Maplin ones are fine and made by Philips I think. I've used them many times and never had a problem. Cheapest Rs these days are 5% carbon films from the likes of RS and they too are excellent quality with tolerance, noise and stability way past what our fathers had available for regular use.

Here's a neat 4 and 5 band resistor calc,

http://www.sizes.com/materls/resistorcolor.htm

[jimangus]

Thanks guys , you have all put my mind at rest, i can solder them in now.

[Greg.]

Yes, Maplin resistors remain one of the few things they still sell (I wonder for how much longer) that sound good and are readily and cheaply available although I have to say, these days I prefer to phone RS and have them delivered free the following day. That's shopping convenience at its best and buying a pack of ten is always useful.

Best wishes,

Greg

[Black Stuart]

Richard,
looking at the resistors used on the Kenwood 990 PCB, most if not all are only 3 band and the deck is about 25 years old - so totally confirms what you are saying.

Black Stuart

[jimangus]

I had never seen a 4 band resistor before these , thanks for the calculators and advise guys, a big help.