Beginner's gripe: 120 ohm vs. 10k resistor

thedanielwilliams · February 15, 2010, 03:51:31 PM

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.

Kearns892 · February 15, 2010, 03:54:46 PM

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

Skruffyhound · February 15, 2010, 05:22:50 PM

http://www.electronics2000.co.uk/calc/resistor-code-calculator.php

mth5044 · February 15, 2010, 05:45:19 PM

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

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.

Talon5051 · 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.

StereoKills · February 15, 2010, 08:34:24 PM

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

PRR · 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.

Taylor · February 15, 2010, 10:46:46 PM

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.

bobp1339 · February 15, 2010, 11:10:30 PM

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.

trendyironicname · February 15, 2010, 11:37:07 PM

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.

MoltenVoltage · February 16, 2010, 01:12:01 AM

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.

nbabmf · February 16, 2010, 03:05:44 AM

I'm colorblind, so I never am without a DMM.

philbinator1 · February 16, 2010, 05:59:39 AM

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

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.

robmdall · February 16, 2010, 01:27:56 PM

On Sale Now:

earthtonesaudio · February 16, 2010, 02:21:47 PM

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.

walker · 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?

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.

mth5044 · February 16, 2010, 02:38:22 PM

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.

dukie · February 16, 2010, 03:44:02 PM

Why dont you hire an Electronics assistant?

Or maybe you can have it for free here http://www.electronics2000.co.uk/.

Since i dont have a DMM it really help me a lot! Packed with great tools too!

Cheers!

gmr1 · 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...

Taylor · February 17, 2010, 02:29:59 PM

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?

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Beginner's gripe: 120 ohm vs. 10k resistor