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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Tue 24, 2012 7:04 am 
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fifties wrote:
I have a couple of little jewels like this in my bench drawer, when I am too tired or alcoholically polluted to discern a value in my age-challenged brain;

Image

Where can I buy one of those?


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Tue 24, 2012 7:26 am 
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Salval wrote:
fifties wrote:
I have a couple of little jewels like this in my bench drawer, when I am too tired or alcoholically polluted to discern a value in my age-challenged brain;

Image

Where can I buy one of those?

http://www.datalizer.com/custom_design_ ... mples.html

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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 2:23 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Shelton, WA
For me it's ROYGBV (pronounced Roy-g-biv) with brown as one and then grey and white at the end.

It got me through the basics a long time ago in a galaxy far away. "live long and prosper."

Am sure it will be needed for the teleporter.

billn


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 2:45 pm 
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Location: Haledon, NJ, usa
Well I was taught the old "bad boys...." mnemonic thing back in my Army days in the early 60s.

But over the years it seems that it all must have penetrated my subconscious somehow.
.... because I never need to refer to it anymore... I just see a color and a number is somehow just automatically associated with it in my mind now... no conscious thought required.

In a way I guess it's a bit like learning to read words from groups of letters or Morse code.
In code at first you eventually begin to auto-associate a sound with a letter.... but soon you advance to the next stage where groups of sounds are picked up as whole words.

Same thing with resistors.. I don't look at each color to calculate the result of total ohms any longer...
..no. Now it's a matter of recognizing the group of colors together like a "word" .. so now I see the total value of the resistor as I look at it as a whole. So I now only see 1k, or 10k, or 330, or 1 meg etc.

But what totally kills it all for me nowadays are the Chinese-made precision resistors!
.... That 4th color screws me up.. and even that wouldn't be so bad.. but their colors are terrible..
.. I cannot tell the difference between red and brown... and red and orange... or blue and gray... especially as the background color is pale blue now too.
PLUS it gets really bad because they also have a 5th color for temp or tolerance or something... so all 5 colors fill up the entire resistor from end to end.
.. that makes it totally impossible, for me, to know from which end of the resistor I should start reading !!!
It is a total mystery (to me) with these things!

I never trust anything I "think" when I see with those "precision things"... so I ALWAYS measure them to test my thinking.. and it's a good idea because I'm usually wrong 1/2 the time... those things are almost a total frustration to me.
Especially when you get something like:
brn-blk-blk-gold-red = 10 ohms 2%
or
brn-blk-blk-silver-red = 1 ohm 2%

For my inventory I keep all of them (regular and precision) all in a carefully arranged box of coin-envelopes with the resistor values written on the envelope in 5 ways
1. The (4 precision) numbers such as 1001 = 1k ====> (2.) the colors Brn, Blk, Blk, Brn
3.) The (3 standard) numbers such as 102 = 1k ====> (4.) the colors Brn, Blk, Red
5. The Value written twice 1,000 and 1k

And after ALL that... I still measure it again before putting it in a circuit!
I have to... because I have also found that being the human I am... I screwed up on about 10% of them when I placed them in my inventory...
So I can't trust anything... lol

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" To be a man, Be a non-conformist, Nothing is as sacred as integrity of your own mind." Emerson


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 4:00 pm 
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Posts: 2361
Location: McPherson, Kansas
I have something similar to the white card...with wheels that turn for the colors. Handy dandy helper.


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 6:03 pm 
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Joined: Feb Sun 17, 2008 11:36 pm
Posts: 1336
Location: Dayton, Ohio
Sometimes, knowing the color code doesn't help. Some foreign made resistors colors fool me or, the coating shifts the colors or, I am going color blind.

Old Ohmite, IRC etc. resistors, I can read ok.

Charlie


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 9:39 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 10086
Location: Valley City ND USA
Aye, There's the rub Charlie. Some you need to replace have the paint bands nearly
completely flaked off, or are burned. Then there is the wattage thing. Of course I'm a novice.


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 11:22 pm 
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Location: Stamford, NY
Here's a great link to a "virtual visualizer" http://halufa.vtec.pt/resistor/ . Spin the wheels and line up the resistor colors with the red arrow! I want one of these for my bench though. Running to the computer gets annoying. Hopefully I'll find one at Kutztown? :)

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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 11:43 pm 
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Joined: Feb Sun 17, 2008 11:36 pm
Posts: 1336
Location: Dayton, Ohio
terry h wrote:
Aye, There's the rub Charlie. Some you need to replace have the paint bands nearly
completely flaked off, or are burned. Then there is the wattage thing. Of course I'm a novice.


I am having trouble with new resistors, orange looks like red, green looks like grey, etc. If the body of the resistor is already green, they have to do something to a green stripe so that it shows up.

New 1/2 watt resistors look like 1/4 watt. (to me).

I used to be able to tell screw sizes at a glance, now they all look one size smaller.


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sat 28, 2012 11:48 pm 
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Location: Chapel Hill NC USA 27514
My main cause for pause is what Tinwhisker mentioned, about the colors not always being even close to any kind of standard, and then you have some of the older sets who's manufacturers decided to use their own code, (run into that more and more now that I have the confidence to do the older sets) and the worst is when the colors are the faint pastels on the really plain Jane axial type that look like they are cut up dowel rods that got held over a smoky campfire. :roll: ~gripin' like an old washer maid~

Haha! Still love it though, no matter how much a PITA some of the work can be. I guess that's really half the fun. You need to employ detective skills along with lots of patience and money.

~blows dust off pulled out pockets~

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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sun 29, 2012 2:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 10086
Location: Valley City ND USA
tinwhisker wrote:
terry h wrote:
Aye, There's the rub Charlie. Some you need to replace have the paint bands nearly
completely flaked off, or are burned. Then there is the wattage thing. Of course I'm a novice.


I am having trouble with new resistors, orange looks like red, green looks like grey, etc. If the body of the resistor is already green, they have to do something to a green stripe so that it shows up.

New 1/2 watt resistors look like 1/4 watt. (to me).

I used to be able to tell screw sizes at a glance, now they all look one size smaller.


I'm with ya on that too Charlie. Red or violet...that looks like burgundy. Only the meter
knows. What value is pink? :)


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sun 29, 2012 6:45 am 
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Posts: 8761
Location: SoCal, 91387
terry h wrote:
Only the meter
knows.

Exactly.

I'll verify what the value should be, by either the print, or if readable, the bands on the original, then select a few out of my resistor stash that I've had for 50 years, and meter until I find one close enough to spec.

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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sun 29, 2012 1:14 pm 
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Joined: Feb Sun 17, 2008 11:36 pm
Posts: 1336
Location: Dayton, Ohio
Yeah, If the resistor is old enough for the colors to be legible, it is old enough to have drifted off value.

Gotta use the meter anyway :roll:

Charlie


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 Post subject: Re: Checking resistors, the lazy way.
PostPosted: Apr Sun 29, 2012 2:40 pm 
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Joined: Jul Sat 05, 2008 3:35 am
Posts: 454
Location: youngsville, NY
There are a couple of i phone apps that get you some of the way. I use one called perfboard. It has info for reading caps as well. It's the caps that usually turn me around, converting .015 nanos to picos for instance requires a second cup of coffee...

-Bill

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Bill

www.billsradioden.shutterfly.com


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