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DIY Stompboxes => Building your own stompbox => Topic started by: plexi12000 on November 15, 2015, 11:02:26 PM

Title: Why I hate metal film resistors!
Post by: plexi12000 on November 15, 2015, 11:02:26 PM
Why aren't they color coded the SAME as other resistors?!  Grrr- dang that's annoying.  hahahaha  :icon_mrgreen:
Title: Re: Why I hate metal film resistors!
Post by: Ben Lyman on November 15, 2015, 11:58:40 PM
I was wondering what was up with that just last night! I've never used them before, just grabbed them out of my pre-labeled pile, then tried to read them later when I was cleaning up... could NOT figure out what they were! So... what is it? A couple color bands on the left and then a black+red bands= multiply by 3? Instead of just using an orange band? I'm confused
Title: Re: Why I hate metal film resistors!
Post by: amptramp on November 16, 2015, 12:08:05 AM
In the good old days of 1930's radios, the resistor markings were simple.  Just remember BED = body, end, dot.  The body colour was the first digit, the end was the second digit and the dot in the middle was the multiplier.  Right now I am looking at a red body, green end and orange dot.  25K.  Most of the metal film resistors I have in my stock have the resistance printed as a number on the side so 1003 would be 100K and 6141 would be 6140 ohms.
Title: Re: Why I hate metal film resistors!
Post by: R.G. on November 16, 2015, 12:21:14 AM
It's really simple. They **are** coded the same way as other resistors, at least the color-banded ones are.

It's the same BBROYGBVGW code. It's just that for 1%, you need one more band. The first **three** bands are numbers, the fourth band is the number of zeros.

Mother Nature (and the resistor manufacturers) are just offering you some light mental exercise.

A sneakier and quicker way is to leave your ohmmeter on and weight the probes down so you can just drop a resistor across the metal  ends and read the resistor directly.

Sometimes cheating is faster.   :icon_biggrin:
Title: Re: Why I hate metal film resistors!
Post by: plexi12000 on November 16, 2015, 01:03:04 AM
just from memory.....i was looking at some 33k's last night.  i think it was orange-orange-black-black.  the 10k's i have are similair....black-yellow and more black.

others are the same.  the first band is usually "correct", maybe two....then the rest are ""different".

i like the carbon's...i have lots of those memorized and don't get them mixed up by accident!  :icon_lol:
Title: Re: Why I hate metal film resistors!
Post by: bloxstompboxes on November 16, 2015, 09:10:25 AM
You could be like me and be colorblind. I label everything from the start and I don't remove it from the package until it is needed. I then staple it closed or reseal it if it is a resealable bag type. Everything is labeled ahead of time. Even parts bins have the color coded parts still in the labeled bag. If one of my kids, or the wife, decided to knock over my parts bins, I'm ok and they don't get mixed up.

The things us handicapped people have to go through. I wonder if I could get a handicap sticker/tag for my truck?
Title: Re: Why I hate metal film resistors!
Post by: duck_arse on November 16, 2015, 09:27:43 AM
the 1% that always gets me reads, from the right - brown - black - black - black - brown. I never know which end is which.
Title: Re: Why I hate metal film resistors!
Post by: Cozybuilder on November 16, 2015, 09:31:57 AM
The 12K's too- brown red black red brown
Title: Re: Why I hate metal film resistors!
Post by: anotherjim on November 16, 2015, 10:29:38 AM
The dark background colour messes them up for me, Purple/Violet sometimes seems brown. Then again I've had carbon resistors with orange looking like red or vice-versa.

BTW, having difficulty telling purples and browns apart is, I'm told, a sign of cataracts developing. I do!
Also, of course, we're told that men do not do colour shades. I suppose we should be glad we don't have to distinguish between malachite and teal - they're all green to me!

As I usually get them on tape bandoleer, I read & measure then write on the tape.
Title: Re: Why I hate metal film resistors!
Post by: J0K3RX on November 16, 2015, 12:00:09 PM
Metal film really suck if you're color blind...  :o My meter is my friend!
Title: Re: Why I hate metal film resistors!
Post by: wavley on November 16, 2015, 12:54:33 PM
I have an old meter on my bench that I leave on just for double checking resistors before I solder them in just in case I read a color wrong.  I'm a bit red green color blind so both brown and blue resistors give me a little trouble sometimes, so I actually do exactly what RG suggests, there are two probes on my bench just for dropping resistors on.
Title: Re: Why I hate metal film resistors!
Post by: plexi12000 on November 16, 2015, 12:57:37 PM
Quote from: bloxstompboxes on November 16, 2015, 09:10:25 AM
You could be like me and be colorblind. I label everything from the start and I don't remove it from the package until it is needed. I then staple it closed or reseal it if it is a resealable bag type. Everything is labeled ahead of time. Even parts bins have the color coded parts still in the labeled bag. If one of my kids, or the wife, decided to knock over my parts bins, I'm ok and they don't get mixed up.

The things us handicapped people have to go through. I wonder if I could get a handicap sticker/tag for my truck?


hahaha-- try it- it would be worth it to see the expression on the bureaucrats faces!

yeah....when i buy new ones now....i keep them 'catagorized'.  i have a few handfuls of older 'vintage' Iskra's in bags.....pain in the ass!  -lol
Title: Re: Why I hate metal film resistors!
Post by: Kipper4 on November 16, 2015, 05:36:28 PM
I too am colour blind. Which is why like the others I label stuff and use meter and componant tester to ensure correct values when needs be.
And yes I would much rather try reading the colour bands on carbon resistors if forced.
Although I think it's a great skill to have to be able to read the bands.
Title: Re: Why I hate metal film resistors!
Post by: bloxstompboxes on November 16, 2015, 05:59:02 PM
I was so worried when I got this job that I was going to have to deal with color coded resistors, or anything for that matter. Luckily, the oldest product still made in the building is still mostly SMD with some through-hole transistors. It's funny, because my home theater system by the same parent company is loaded with through-hole resistors.
Title: Re: Why I hate metal film resistors!
Post by: Quackzed on November 16, 2015, 11:23:14 PM
i hate em too. its like you spend years learning math, then they move over to the 'new' math.  :o
its sadistic!  >:( and isn't a 100k resistor still 100k??!!? just less imprecise? why do you need another band? doesn't the tolerance band do that job?!? i dont get it... imho it's annoying and less intuitive and i don't like it!!!
(https://simplysenia.files.wordpress.com/2014/11/refusing-dinner.jpg?w=750)
Title: Re: Why I hate metal film resistors!
Post by: MrStab on November 17, 2015, 01:51:18 AM
i'll test a sample or two from a strip then just depend on bag labelling, because like some of the other guys, i'm partly colourblind. and sometimes the lines wiggle, but i think that bit was my own fault.

breadboarding can be quite wasteful sometimes when you strip everything off it and it's far too much effort to measure each part, but i do make an effort to salvage & test resistors from circuit regions i recognise.
Title: Re: Why I hate metal film resistors!
Post by: Electric Warrior on November 17, 2015, 08:11:53 AM
I'm not colorblind and still have troubles reading them. Much prefer carbon films or carbon comps.
Title: Re: Why I hate metal film resistors!
Post by: antonis on November 17, 2015, 09:00:24 AM
I assume that you don't use your Ohm-meter when populating a board... :icon_redface:
Title: Re: Why I hate metal film resistors!
Post by: Electric Warrior on November 17, 2015, 09:30:07 AM
I do.  ;D
Title: Re: Why I hate metal film resistors!
Post by: Vitrolin on November 17, 2015, 05:46:07 PM
im not shure i understand the problem for those who dont have problems with colour blindness.
if you know the colour code its quite easy its almost the same...
theres added the tolerance and sometimes (6-bands) the temperature coeffecient.
you'll get used to it pretty fast,
remember the wider band is to be ignored if you just want the value, it also indicates last digit..


but yes i also use a multimeter when tired and/or lazy
Title: Re: Why I hate metal film resistors!
Post by: Joe on November 17, 2015, 07:30:58 PM
I have trouble reading these too. They should have made the background color gray instead of green.

A few years ago I needed some 2W resistors for a project.. Fortunately they were all the same value, but this time the background color was blue. Ugh.
Title: Re: Why I hate metal film resistors!
Post by: Electric Warrior on November 19, 2015, 03:00:07 PM
Yeah, the colors of the stripes are very hard to read against a blue background, especially if the stripes are semi translucent.
Title: Re: Why I hate metal film resistors!
Post by: rumbletone on November 19, 2015, 05:51:05 PM
On a related note, do any of you use an 'auto ranging' meter for measuring resistance? Often it's not a big issue (i.e., if I already know the ballpark resistance) but there are many times where not having to find and select the range would save a ton of time - like when sorting through a pile of random resistors, which inevitably accumulates on my bench. Also, more often I find myself not relying on reading the bands -  I have no issue with the schema, but sometimes have trouble distinguishing the colors (grey, red/brown on some resistors, etc.) so I use the DMM to check my reading of the colors.
Title: Re: Why I hate metal film resistors!
Post by: DDD on November 19, 2015, 06:01:59 PM
I am a great fun of SMD, hence I am free from hate to the color-coded resistors.
But at the same time I hate SMD capacitors since they have not any coding at all.  >:(
Title: Re: Why I hate metal film resistors!
Post by: nick d on November 19, 2015, 08:23:55 PM
      At the end of the day , carbon comp , carbon film , metal film , whatever - if in any doubt , you've got a DMM , use it ! It you haven't got one , you really shouldn't be doing this stuff !
Title: Re: Why I hate metal film resistors!
Post by: LightSoundGeometry on November 19, 2015, 08:32:29 PM
they are five banded with the multiplier or tolerance i think ..I agree, the brown or neutral background is best. 4 banded carbon comps are easy to read
Title: Re: Why I hate metal film resistors!
Post by: R.G. on November 19, 2015, 09:24:46 PM
Can you imagine color coding bands or dots on 0603 SMD resistors?

It would work fine from the manufacturing standpoint, but I'd have to get out the old B&L Stereo Zoom to see the dots. 0603s are almost invisible by themselves, let along 0201's. Yes, those exist.

Color coding comes from a time when there was no cost effective way to print numbers on parts at all, and when the parts were on the order of 0.5"/12mm or larger. Like so many things, it's a historical note that's really beyond it's "sell by" date.
Title: Re: Why I hate metal film resistors!
Post by: duck_arse on November 20, 2015, 08:43:55 AM
when I'm doing 1206 caps, I put a diff colour dot for each value on them, while they are still in the carrier strip. note the colour/value on the schem, away we go. away might be an overstatement.

there was a time when metal film resistors were (here, commonly) either kack green or deep dark red body colour. they never used to be a problem band reading (but I don't suffer colour blindness, and my eyes were younger then).

[edit :] also, the resistors were 2%, no fifth band.
Title: Re: Why I hate metal film resistors!
Post by: anotherjim on November 20, 2015, 10:38:45 AM
Must be 40years ago, I saw 1% resistors with body black and the value written on them - still have few in a bits tray. Odd values too, anybody need a 2.67k resistor?  I also remember colour banded 2% being common - don't suppose there's any point in 2% now when 1% are cheap.

Isn't it great that IC's always have the part number printed? Except...except it's in feckin' invisible ink these days AND it rubs off easily. Grrrr...
Title: Re: Why I hate metal film resistors!
Post by: Vitrolin on November 20, 2015, 04:16:38 PM
SMD resistors som times have very easy numeric code or they have this alpha-numeric code withut any logic:
http://www.talkingelectronics.com/projects/ResistorsMadeEasy/SMD-Resistors-EIA-Markings.html (http://www.talkingelectronics.com/projects/ResistorsMadeEasy/SMD-Resistors-EIA-Markings.html)
Title: Re: Why I hate metal film resistors!
Post by: Quackzed on November 20, 2015, 11:35:19 PM
when your printing on a part that's  smaller than a grain of rice, it's hard to see the logic either way...
(http://i.imgur.com/Tcmvmjd.png)
:icon_lol: see what i did there?   :icon_lol:
Title: Re: Why I hate metal film resistors!
Post by: mremic01 on November 21, 2015, 02:29:24 PM
Quote from: anotherjim on November 20, 2015, 10:38:45 AM
Odd values too, anybody need a 2.67k resistor?

Bill Finnegan might be interested.
Title: Re: Why I hate metal film resistors!
Post by: Ben Lyman on November 21, 2015, 04:41:33 PM
Quote from: Quackzed on November 20, 2015, 11:35:19 PM
when your printing on a part that's  smaller than a grain of rice, it's hard to see the logic either way...
(http://i.imgur.com/Tcmvmjd.png)
:icon_lol: see what i did there?   :icon_lol:
I had to zoom in all the way but, yes, I saw it!
Title: Re: Why I hate metal film resistors!
Post by: PRR on November 21, 2015, 09:44:52 PM
> an 'auto ranging' meter for measuring resistance? ... not having to find and select the range would save a ton of time

Pay less (manual ranging) or pay more (range button).

Or see if your present meter has a RANGE button.

When poking 120V outlets I always put my good meter in 199.9V range. Otherwise it starts at milliVolts and chug-chug-chugs up.

I have used this for Amps. I wanted the start-up surge of a pump. The surge is shorter than the first glug of auto-range, gave stupid-low readings. On 199A range it caught the 35 Amp surge.

I hadn't tried this, but just did. Both my good "auto" meters, I can put in Ohms then tap RANGE for the several ranges.

It is a nearly-zero-cost feature for the meter-maker (mostly the cost of the button); though I suppose they save it for the higher-price models.