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I am looking into getting a triple output lab power supply. Do you guys use / recommend any specific brand or power supply? I could use 3 seperate supplies, but then I would need a way to tie the grounds together. Please give me a few recommendations.
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Well they can be on the pricey side. I think most are now made in China and so cheaper then they use to be. If you don't mind used then E-bay can find many HP lab supplies that were among the finest ever made.

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If they work and were taken good care of, then who cares if they are used? Beggers can't be choosers... Ideally I would get a BK Precision 9130, but that will never happen... Do you have any recommendations?
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You can always tie grounds together with cables, or use a metal shunt from each negative terminal to the earth (green terminal) then they'll all be implicitly connected together (but don't do this if you need them to be floating supplies).

I like using 3 single-output supplies. Put them side-by-side and they take up about as much space as a triple-output, and it's easy to just pick one up and replace/transport it, etc. Electronix Express has some inexpensive models:

http://elexp.com/tst_3003.htm

$85 for 30V/3A isn't bad

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Again HP are my favorite:

http://business.shop.ebay.com/i.html?_nkw=HP+triple+power&_sacat=92074&_odkw=&_osacat=92074&_trksid=p3286.c0.m270.l1313

http://business.shop.ebay.com/i.html?_nkw=HP+dual+power&_sacat=92074&_odkw=HP+triple+power&_osacat=92074&_trksid=p3286.c0.m270.l1313

 Test equipment like this can last a lifetime if one buys quality up front.


Lefty
« Last Edit: August 04, 2010, 01:17:59 pm by retrolefty » Logged

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I think the three single output idea would be better. Like he said, I could pick one up and take it with me. I could also just get 4 female banana plugs and internally connect them in a little project box, correct?

Also, I am thinking of starting some more threads about more lab equiptment like: Multimeters, Capacitance meters, O-scopes, Ect. Is that a good idea? Also, do you have any other ideas for those type of thread (Other types of equiptment.)?    
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I could also just get 4 female banana plugs and internally connect them in a little project box, correct?

Yes, but unnecessary. You can daisy-chain banana plugs from one supply to another (get the ones that have both a banana plug and a socket on the same end).

Quote
Also, I am thinking of starting some more threads about more lab equiptment like: Multimeters, Capacitance meters, O-scopes, Ect. Is that a good idea? Also, do you have any other ideas for those type of thread (Other types of equiptment.)?

Errr.....can't hurt I suppose. This is Bar Sport after all smiley

There's a current thread on Slashdot about oscilloscopes:

http://ask.slashdot.org/story/10/08/03/2331257/Oscilloscopes-For-Modern-Engineers

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If they work and were taken good care of, then who cares if they are used?

Here's the problem: How will you know this? Just because a seller says so, doesn't mean much...

If you have a power supply, you don't know if it is calibrated, whether the output matches what the readout says, etc. I bought a couple of ECI power supplies from Apache Reclamation (triple output: 1 variable 0-25VDC 1.25A, 1 fixed 5V 1A, 1 fixed AC output, I forget the specs); I paid $25.00 each for them (over the weekend I picked up the "matching" frequency counter for $25.00) - they were in really rough shape, but they seemed to work. I managed to get the service manual from ECI, so I can calibrate them myself.

You may or may not be able to do the same with another brand of used power supply; sometimes, even if you can get the service manual, you'll spend a lot for it...

Power supplies are one thing, though - test equipment is a whole 'nother ball-o-wax. For o-scopes and meters, I would -not- purchase over Ebay, and I would really shy away from "used", unless I was allowed to power it up, and run some simple tests with the built-in test signal. Especially in the case of an o-scope, you would want to get familiar with how to do this, and how to read the scope, so you know what you are looking at is right. This is especially true in the case of an analog scope.

I got my Tektronix 2213 off a guy on Craigslist; he said he had it calibrated by the factory, and gave me everything to prove it, allowed me to power it up and test it. It passed perfectly, with the minor exception of the implosion shield being fogged (found another to replace it, though). If you test a scope, and you know what you are looking at, and you feel that something just doesn't seem right, follow your gut and keep looking; if you have the manual, there is usually a section that details how to calibrate it yourself, but you need a special piece of equipment called a "calibration signal generator" (which needs to be in calibration itself, of course!); these are anything -but- cheap. So if the scope doesn't seem right, pass it up.

For all of these reasons, it is generally best, if you can afford it, to purchase test bench items new - unless you know what you are looking at, and know how to test before you buy (and the seller will allow you to test). I am not saying you can't find good deals on the used market, but you have to be careful, and examine everything thorougly before you plunk your money down, or you could be looking at throwing good money after bad...

 smiley
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I have a dumpy old analog elenco, but it served as a test station here at work for a number of years, aside from the 25lbs of dust inside it works fine, and is calibrated pretty well though there is always more room for error in a analog system
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