power supply

hey all

I am wondering if this would be a good starting out bench power supply
15V 1A Precision Variable DC Power Supply Clip Cable Digital Adjustable Lab Grad | eBay

can you tell me yea or na

No. There is no constant current function, the voltage is on the low end of "standard", it's made in china, it's not a good price/value, and the current is very low.

Get this 0-30V 0-5A one instead. It has constant-current capability, twice the voltage range, 5 times the current range, fine-adjust for both voltage and current, a grounding point, and probably has better regulation in general.

I have no affiliation with this seller; I just watch ebay closely for used power supplies.

I'm with Cyp, if you're going to be in the laser hobby constant current mode on a PSU is a must.

You're in the USA so you can find very good deals on ebay for used PSU's.

I have one like that too.
Get it -- you will need it.
HMike

thanks for the feedback

how about this one http://www.ebay.com/itm/30V-5A-110V...506?pt=LH_DefaultDomain_0&hash=item5ae77ea1da

or this one http://www.ebay.com/itm/15V-2A-Prec...416?pt=LH_DefaultDomain_0&hash=item4d1c38f460

or this one http://www.ebay.com/itm/New-30V-5A-...724?pt=LH_DefaultDomain_0&hash=item48655f29b4

That is still a bit limited, I have to agree with Cyp and ARG. Get one that's at least 30v 3A at a minimum, that's what mine is and I paid about $80 I think. I recommend getting something of good quality.

Alan

so this one would probably be the best one yes New 30V 5A 110V Precision Variable DC Power Supply Digital Adjustable Lab w Clip | eBay

Why not the one Cyp linked? It's cheaper.

Also, if you do get a power supply the leads that you get with it will almost always have a really high resistance. Find some banana plugs, gator clips and a bit of lamp cord to make your own ones that won't suck.

the one crp posted has twenty dollars shipping is why its fourty plus twenty i can get the one i posted with free shipping

Ah, didn't catch that. Just said no shipping to Canada for me

Just get the one I linked. Trust me. When it comes to something as useful as a bench power supply, you don't want to buy the cheapest piece of shit you can find. It WILL break down.

Those cheap chinese supplies are cheap for a reason. I bought one a few years ago and boy do I regret it. It can't regulate worth a damn in current-mode. It died a few months in - fixed a loose cable. Died a few weeks later - fixed a bad comparator. Died a few weeks later - shorted pass transistors due to heat sink overheating. I had to replace the pass transistors and add a bunch of heat sinking to make it somewhat usable again. It's still on my bench and I use it for some things where I don't care about the regulation.

ALSO, do NOT trust ebay test leads. No one checks them, but they're 28 awg or smaller (so they can save 6 cents on copper!) which means they're useless for anything but a voltmeter or for low current. Learn to make your own test leads - get banana plugs, alligator clips or mini grabbers, and solder them yourself using a more respectable 18-16awg. Lamp cord is perfect for that.

A month or so ago, after reading Cyparagon's advice on the forum and after watching some vids on EEVBlog I went about and bought a pair of nice old HP power supplies on eBay (one was this one). They work great, are easy to use, accurate, and a pretty good deal considering how much they cost when made. I especially sought out models that had nice 10-turn pots on them for control, as well as constant current and voltage. They also still work pretty much exactly how they did when they were built because they were built so well.

Bionic that is a little out side of my budget I have around 60 to 70 dollars I may end up building one from a atx power supply I just kind of lost as of right now.. I want one but I will have to save for a bit to get it any way thanks guys for the feedback


I work for 12 bucks a hour and have a large family so extra money gets split between my wife and I and it usually about twenty bucks or so a pay check so I will have to save for a month and half to get this... This is not a sob story just a statment of fact

All the more reason you don't want to get the chinese supply. You're gonna be extra pissed when it breaks

It doesn't sound like starting a home lab is a good idea at this point in your life. You can make a home-made supply out of an atx and a couple of LM317s, but that's low current low voltage and no readout.

What sorts of things do you need to power?

Maybe even build your own; using the ATX for the input. I was tempted to do this, but didn't want to deal with casing it all and stuff. Otherwise, the parts really aren't that expensive, and a good learning experience. There's a good series explaining how you could go about such a thing on EEVBlog. Here's the first video.