This isn't so much a question as it is a mere gripe... While populating a BSIAB2 board from Generalguitargadgets, I ended up with three very similar resistors in hand: two 10Ks (brown-black-black-red-brown) and a 120 ohm (brown-red-black-black-brown). My multimeter's in a box several thousand miles away--how frustrating!
Do any of you also have trouble identifying the tolerance band on five-band resistors? They often seem pretty evenly spaced to me.
Haha, this is me every day. I'm colorblind so unless I am getting a resistor directly out of its marked bag, I have to pull out the muimeter...
So to answer your question, yes i have trouble with them :)
http://www.electronics2000.co.uk/calc/resistor-code-calculator.php (http://www.electronics2000.co.uk/calc/resistor-code-calculator.php)
I remember helping a guy who was making a BMP with the same problem!
Quote from: Skruffyhound on February 15, 2010, 05:22:50 PM
http://www.electronics2000.co.uk/calc/resistor-code-calculator.php (http://www.electronics2000.co.uk/calc/resistor-code-calculator.php)
A calculator is good, but when you can't tell which end it is starting from, it really is no help ???
I think your best bet, really, is multimeter. If you need one, you can pick up really cheap ones at radio shack and the like.
I have to use a magnifying glass if I do not have a multimeter. I hate getting old.
Fortunately when I got my resistors they were in ammo pack style, with the values written on the paper ends. If any come loose from that, they go into a pile that is *to be determined later*. I too have trouble telling which end is the starting end, especially if they both start with brown :)
9V batt, LED, mystery resistor.
A 120 will be very bright.
A 10K will be very dim.
K-Mart may have a $10 DMM; cheaper than flying home to raid your box.
I only buy resistors that come in labeled baggies - I can't stand messing with the bands, even have the luxury of online calculators. Same with caps - I don't like straining my eyes to read tiny values - and I'm only 23.
It seems pointless on some of the 1% metal resistors to even use the color bands, as I cannot tell the direction either.
I always wind up using the meter.
That calculator has become indispensable to me. I used to could read color code quick but now, nope. The capacitor calculators in there are worth their weight in gold also. I used to waste way too much time before and don't think I could go back to not having that up on my monitor every time i build.
Quote from: PRR on February 15, 2010, 10:33:07 PM
9V batt, LED, mystery resistor.
A 120 will be very bright.
A 10K will be very dim.
K-Mart may have a $10 DMM; cheaper than flying home to raid your box.
+1 on the LED testing.
Harbor Freight sells DMMs for $3 or $4 regular price with battery, and sometimes for $2 on sale.
I'm colorblind, so I never am without a DMM.
Quote from: Talon5051 on February 15, 2010, 08:28:40 PM
I have to use a magnifying glass if I do not have a multimeter. I hate getting old.
Ha! Luxury! I'm only 32 and I have two magnifying glasses duct-taped together to identify parts. Maybe a walking stick
is in order, to complete the look ;D
But seriously, the resistors from dick smith are coloured DARK GREY (!) and it's very hard to see the colour bands (even
if i could see them)...so yeah i always use the multimeter if i'm not sure.
On Sale Now:
(http://i415.photobucket.com/albums/pp231/robmdall/Image.jpg)
I have one of those. My only complaint is the socket for transistor testing is a little flaky and I'm not sure I trust the number it gives for hFE... but those are pretty minor complaints for a $2 meter.
when testing resistors with a DMM, if it comes up with the right number, does that also indicate that the resistor is not fried? If it was fried, would it just say zero?
I just bought a velleman DVM850BL (http://www.vellemanusa.com/us/enu/product/view/?id=350297) for $18 and I thought that was going cheap. (and it seems a little wonky) I can't imagine a $2 meter working right.
Quote from: walker on February 16, 2010, 02:32:19 PM
when testing resistors with a DMM, if it comes up with the right number, does that also indicate that the resistor is not fried? If it was fried, would it just say zero?
If a resistor is resisting, I'd say it's doing it's job.
Why dont you hire an Electronics assistant? :P Or maybe you can have it for free here http://www.electronics2000.co.uk/ (http://www.electronics2000.co.uk/).
Since i dont have a DMM it really help me a lot! Packed with great tools too!
Cheers! ;)
I hate to admit this, but often I wont trust the banding and do a quick check on every resistor with the DMM before soldering it in... OCD FTL...
Quote from: gmr1 on February 17, 2010, 09:08:39 AM
I hate to admit this, but often I wont trust the banding and do a quick check on every resistor with the DMM before soldering it in... OCD FTL...
It's not that crazy... I have seen reports of really cheap resistors being repainted with other values and tolerances. Also seen cheapo caps encased in fake cases to look like more expensive caps. I don't know why - what kind of profit could you really make on an operation like that?
Quote from: PRR on February 15, 2010, 10:33:07 PM
9V batt, LED, mystery resistor.
A 120 will be very bright.
A 10K will be very dim.
Thanks, PRR. This'll definitely help!
Quote from: walker on February 16, 2010, 02:32:19 PM
when testing resistors with a DMM, if it comes up with the right number, does that also indicate that the resistor is not fried? If it was fried, would it just say zero?
probably the other way around. Metal film resistors should be fusing, so rather than reading zero, a shorted closed circuit it would break the circuit and have a practically infinite reading. Good question though as I'm curios to know if a resistor can be partially damaged and still read correct.
I've had the same problem of looking at resistors upside down in a circuit where they look identical. There's little dfference.
I was working for an amp manufacturer and know that you do have to be weary of relabelled stuff. I saw something with cheap HT electros that were like 22uf wrapped in another casing, wrapped in another another casing, then labelled as 47uf. It was like a Russian doll! No chance the vents would ever work if they blew. Certain companies/countries do dodgy things... Your supplier might not pickup on faults too, so it's up to you.
so then how do you tell if a resister is toast? Or for that matter a Cap, diode, or other component. My DMM has a spot for the transistors. I'm asking because I recently caused a little fire in a volume pot, I think by hooking up v+ wrong, and I wonder what other parts in lit up. Also, none of my circuits ever work.
Resistors and diodes rarely get fried in 9v pedals. Electro caps pop loudly, smoke, and the metal vent splits or domes if it's fried. I've never managed to fry a non-polarized cap, so I don't know what would happen, but I doubt you've done it. When things blow because of wrong power hookups, it's usually electro caps, ICs, and the occasional pot, as you've seen.
Quote from: walker on February 17, 2010, 06:44:52 PM
so then how do you tell if a resister is toast? Or for that matter a Cap, diode, or other component. My DMM has a spot for the transistors. I'm asking because I recently caused a little fire in a volume pot, I think by hooking up v+ wrong, and I wonder what other parts in lit up. Also, none of my circuits ever work.
Dude..i feel your pain :) do you breadboard stuff? that's what i've started doing, after too many disapointing failures...going back to basics too, i tried to run before walking.
Thanks Taylor, that's good to know. Philbinator... I just started. I build myself a "beavisboard", and have tried several circuits, non have worked right yet.
Quote from: walker on February 17, 2010, 09:20:46 PM
Thanks Taylor, that's good to know. Philbinator... I just started. I build myself a "beavisboard", and have tried several circuits, non have worked right yet.
I got 2 books by brian wampler, "how to build fx" and "how to mod fx"...they have great starting projects in them. and if you join up to his mailing list
you get huge discounts, i think i got mine for US$15 each when they are usually $39, i believe. one of the projects is a "one component at a time" type
of deal, where you breadboard it and can hear the diff with each new component. very cool!
Edit, i should add they are e-books.
wouldnt it be easier if they just wrote 10k etc on the things!............. :icon_twisted:
nothing is simple i guess!............ :icon_rolleyes:
Quote from: deadastronaut on February 18, 2010, 03:18:43 AM
wouldnt it be easier if they just wrote 10k etc on the things!............. :icon_twisted:
nothing is simple i guess!............ :icon_rolleyes:
There are actually resistors with a value code written on them:
(http://pws.cablespeed.com/~danielzink/musical/condorboard.jpg)
But it's not the value, but a code of significant bits followed by a multiplier. Still a little confusing, but easier to read than bands to me.
The reason the band system is done more commonly is that they can be read no matter how they were inserted. The bands are visible all the way around the part, as opposed to those coded ones which can only be read if inserted with the part number up. In cheap 'n' fast manufacturing, having to orient the resistor up wastes expensive microseconds.
they look like little hot dogs...lol..
And this led me to an idea, that I must build to myself. A experiment board which is very easyli conntected with multimeter, by somekind of sockets that suits with multimeter fires or something. So when I am building something and I doubt, I just plug a component in the board and ready. Could not think of a faster way to do it.
Quote from: served on February 18, 2010, 08:09:57 AM
And this led me to an idea, that I must build to myself. A experiment board which is very easyli conntected with multimeter, by somekind of sockets that suits with multimeter fires or something. So when I am building something and I doubt, I just plug a component in the board and ready. Could not think of a faster way to do it.
I wound up hacking an old pair of leads and 20ish solid core wire so that while i'm breadboarding I can throw those in instead of the probes and plug them into dif places on the board and they'll stay. I have alligator clips permanently soldered to a pair also.
ZIF sockets are excellent for testing chips and other components. The ones with the little lever work best.
This is just one example:
http://www.mouser.com/ProductDetail/3M-Electronic-Solutions-Division/224-1286-00-0602J/?qs=sGAEpiMZZMv9Q1JI0Mo%2ftTqfDQB3DcEg
I'm glad that I'm not the only one that can't figure out these five band resistor codes. :icon_lol:
I have to admit that I only bother with the codes if I'm looking for something in my junk pile. Otherwise all my values are marked on their containers and I'm as anal/OCD as Greg because I check every resistor as I build something. Never had the "same code different value" problem, why I didn't catch the point of the OP.