variable resistor

[anthonyac1]

basically im looking for a variable resistor with a knob or something similiar if you find a bad resistor you can drop in this adjustable resistor as a temporary. i looked at radio chack they have some that say 15k ohms i was told thats the max resistance but it can be set to anything lower but it also said 500 vdc the guy at radio shack said where ever i use it at it must use 500 vdc or elso the resistor wont work properly??? is that true?? what do yall use as a temporary resistor???

[orion242]

Any potentiometer should work as long as you don't exceed the power rating. 500vdc would be the max, but it would work fine at lower voltages. Asking the RS guys about their components is like asking bus driver how to fly the space shuttle.

[alcomech]

I wonder if a decade box would work?

[jrevans]

Asking the RS guys about their components is like asking bus driver how to fly the space shuttle.

Isn't that the truth! They have officially morphed into a mobile phone sales store, but I'm thankful that they at least still carry some electronic parts.

[simux]

I basically try to keep a wide assortment of resitors that I normally need. If you have a good assortment you can combine resisters in parallel to lower the resistance and connect in series to raise the resistance.

[billygoat22]

like one of guys said, a box w/ switches to set approximate resistance, and maybe the adjustable one to set exact.

[controldude]

I am a ham radio operator and today they should change their name to Cell Phone Shack I'm suprised the guy even knew where the resistors were let alone variable our store is a complete loss. But I bet he asked if you needed batteries! got to ebay you can usually get decade boxes fairly cheap.

[osiyo]

basically im looking for a variable resistor with a knob or something similiar if you find a bad resistor you can drop in this adjustable resistor as a temporary. i looked at radio chack they have some that say 15k ohms i was told thats the max resistance but it can be set to anything lower but it also said 500 vdc the guy at radio shack said where ever i use it at it must use 500 vdc or elso the resistor wont work properly??? is that true?? what do yall use as a temporary resistor???

Well, it's like a lot of places these days. Pretty common to walk into a Radio Shack, or a hardware store for that matter, and find that they have precisely 1 person on staff who has a clue about the technicalities of what they're selling ... and that person isn't there right now. The rest are just sales clerks.

Anyway, I have a couple potentiometers in a kit I keep in the truck, but to tell the truth ... I pulled 1 out and used it to test something 3 times in the past 10 years. None of those recently.

Too much hassle and bother frankly.

How many different resistor value requirements do you actually have to deal with?

In my case there are 2 I need a lot. Another 4 I need less frequently but often enough to keep a supply handy. I keep them in a middling size plastic parts case. Along with some other misc devices such as transorbs, diodes, these tiny little fuses needed by some items I work with, etc. I find the plastic parts case handly as I can readily find what I'm looking for and immediately see if I'm getting low on something and need to replenish the stock.

Just for "in case of need" sake, I also bought one of the large variety assortment bags of resistors, from Radio Shack. I forget which, but it's got something like 50-60 different values. I've actually broke that out more than I have the potentiometers. Handy if you just have to make do ... NOW ... just to get something working.

The problem with potentiometers is that you either need a variety with different ranges or you're gonna have the devil of a time "dialing" one in reasonably. For instance if you need a 500 ohm resistor and all you've got is a 15k pot, it can take a light touch to get the setting just right. And with the cheap pots, breath on it wrong and you'll need to readjust it.

Just my thoughts.

Myself, I'll stick with my method. Those "most used" resistors I keep a supply of, its not that many different ones, and I buy the precision resistors. It just avoids the hassles. And I'm not fond of redoing stuff. Coming back to remove a pot and install a resistor doesn't appeal to me.

[alcomech]

Osiyo thanks for the link. That will make for good reading one day

[BamaCool]

Rat Shack SUX......If you need electronics......http://www.digikey.com/

[orion242]

My version of a decade box.

http://www.jameco.com/webapp/wcs/sto...10001_81832_-1

[billg]

It was nice to be able to go to Radio Shack years ago. At one time they were the only game in town for the average Joe because many other places didn't want to sell to non businesses.

[anthonyac1]

i appreciate everyones input and advice. mainly i need it for failed thermistors as a temporary fix. honestly i rarely see them go bad but i like to have everything on my truck. i was checking out the variety pack of resistors i was going to get a pack then i heard a guy mention get a variable resistor with a wide range hmmm that sounded interesting so thats why i was asking for your input. i figured the guy didnt know what he was talking about at radio shack but i wasn't 100% sure myself so i wasnt going to knock his advice. im going to pick up a pack of resistors just to have on the truck just in case

[MechAcc]

Try Allied Electronics. They are pretty good at shipping same day.

[DeltaT]

I made my own decade box for just about any combo I could ever run across. I'll take some pictures and post as soon as I can.

I also carry a commissioning tool, made by Johnson Controls I think, for the same purpose.

[orion242]

mainly i need it for failed thermistors as a temporary fix.

You may want to just buy bare thermistors. I got 100 10K type 2 for less than $25 some time ago. They come in handy for temporary use.

[DeltaT]

Here is what I made. I have ranges for everything.

[alcomech]

This is what I use.