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Variable DC Power Supply - Which one?

jmgallego

jmgallego

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I see the time for me to get a nice Variable DC Power Supply has arrived.

With new laser diodes out there, my interest to build new portable and bench lasers has brought me back to this hobby. So, I am thinking on getting one, however, I do not which one.

There are a few thread here that recommend some of the ones available in eBay which are quite attractive and inexpensive (for less than $120), some with free shipment (to outrages $120 S&H) and warranties from 30 days to 1 year.

The standard specs of 30v and 5A max seems, at this time, reasonable since most of the current visible laser diodes are below that voltage and amperage (with around 3 amps for the new 445nm laser diodes). However, for high power infrared lasers, the 5A may be a limitation, as some will go up to 12A, so a 30v 20a may be useful, but they run in the $150-$250 price range. And... then there are the 40A and the 60A ones but I think is way to high for laser diodes (with price above $250).

As someone running and testing laser diodes, if you were to buy one, which one would you select and why?

Here is an eBay search link to those available for 30v 5a for less that $120:

30v 5a dc power supply | eBay

And here is an eBay search link to those available for 30v 20a for less that $250:

30v 20a dc power supply | eBay

Some of the ones I found interesting (in no particular order) are:

Precision Lab PS305 30V 5A HQ Variable DC Power Supply with 30 days guarantee.

X-TRONICTM 6000 SERIES - MODEL #6080 30V - 5A INDUSTRIAL/COMMERCIAL POWER SUPPLY with 1 year guarantee.

MASTECH HY3005D DC Power Supply Lab Grade Precision Adjustable 30V 5A Backlit

MASTECH VARIABLE DC POWER SUPPLY 30V 20A HY3020E 600W

Linear Regulated 30V, 20A DC Power Supplies TPR Series TPR3020

KXN-3020D High-power Switching DC Power Supply (30V, 20A)

Thanks!
 





I have used a Mastech, but this Extech is a much better supply:
digsupply.jpg

The 4 Digit readout allows plotting diodes with better precision.
Here I am charging the newest lithium ion #18650's to 4.35 VDC in Constant Current mode.
The 5 amp capacity allows charging several cells at once.
Also switching supply takes up less space on bench.
I can get a good price on these, if anybody needs one.

LarryDFW
 
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Thanks Larry... that one on the photo looks like this one:

extech power supply | eBay

Running on EBay for about $215 for new ones and %145 for used ones... nice, but ouch! :cryyy: As LaserSam is asking, how much for LPF members? :D

I like this one because the ranges are selected by pressing any of the three buttons. Most of our work with laser diodes would be in the first button, 16V 5A.

Something to think about... THANKS!
 
LaserSam & jmgallego;

The review button is nice for checking the maximum current setting.

I have used it for several years,
and it has no voltage spikes to take out laser diodes, like the MasTech.

I can sell it for $215.

PM if you need one.

Thanks;

LarryDFW
 
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Nice.... :D

Review button? Sounds interesting, how does it work?

Thanks!

LarryDFW said:
LaserSam & jmgallego;

The review button is nice for checking the maximum current setting.

I have used it for several years, and it is safer on laser diodes than the MasTech.

I can sell it for $215.

PM if you need one.

Thanks;

LarryDFW
Click to expand...
 
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Here is another option, I have found over the years you pretty much get what you pay for and with that said maybe you can use this model, it's made by a well known american manufacturer :D

Now it will depend on what all you plan on using this power supply for but if you are looking for 30 volts @ 5 amps max and OVP & OCP then this may be the one for you, I like mine very much,
with the over voltage protection and over current protection you'll probably never accidentally blow up any thing :D

It's a little price'y but well worth it if you need these features in a bench power supply, and it will last you the rest of your life in case that matters :)

Read the specs they will tell the story>

U8002A DC Power Supply, 30V, 5A | Agilent
 
All bench power supplies have the standard voltage/current limit. The over-voltage and over-current is different from voltage limit and current limit. You need to set each value manually. The over-voltage and over-current is only useful if you have a $$$$$ device that you want to be doubly-sure that you don't adjust the voltage on it by accident. Think of it as having to use two keys to unlock your door instead of one. Added safety, but much less convenient, and not necessary for most cases.
 
Flaminpyro said:
Here is another option, I have found over the years you pretty much get what you pay for and with that said maybe you can use this model, it's made by a well known american manufacturer :D

Now it will depend on what all you plan on using this power supply for but if you are looking for 30 volts @ 5 amps max and OVP & OCP then this may be the one for you, I like mine very much,
with the over voltage protection and over current protection you'll probably never accidentally blow up any thing :D

It's a little price'y but well worth it if you need these features in a bench power supply, and it will last you the rest of your life in case that matters :)

Read the specs they will tell the story>

U8002A DC Power Supply, 30V, 5A | Agilent
Click to expand...

I read the specs, it really is a nice one... sigh! The price is $415 but it seems that you can a quote for less (on the right side of the link). On Ebay is running around $487.79... ouch!

Thanks... This one is on the top of my list right now. The price may put it down on my list :cryyy:
 
Just get a cheap-ass one from China and build your own current regulators from transistors and your own circuits. Then you have ultimate control over your output and if you burn out your power supply, or it malfunctions, you won't affect your stuff.

I bought this one, but I'd probably buy some cheaper smaller ones if I knew what I know know. When I want to regulate current in a precise manner I just use a simple MOSFET based current regulator. If I were worried about the voltage stability I'd just put a linear regulator before it. All these secondary components are super cheap and do a great job.
 
I built my own a while back out of a LM338K. 1.6 - 31.8V, internally thermal and current limited and prettymuch bulletproof. The circuit is right off the datasheet. I just added a transformer, diode bridge, and eBay LED voltmeter.

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