Brads Electronic Projects Forum

30V 5A Precision Variable Adjustable Digital DC Power Supply Regulated Lab Grade

http://www.ebay.com/itm/30V-5A-Precisio ... 58b1aaaffb

This is an Ebay item and I'm wondering what you think of this item. There are more expensive units.

If it's everything it says it is, and it lasts, it sure looks like a good deal.

Garth wrote:If it's everything it says it is, and it lasts, it sure looks like a good deal.

Thank you. What I learned from an Engineer (Chris) is that while it is a good unit, the potentiometer can build up dust or dirt over the years and create noise so the voltage could be set at one voltage and jump up to another voltage before it settles down.

I'm looking for a digital or would that be linear power supply?

Are there any other power supplies for a little more that might be better? I might consider them.
I'd rather buy the right tool and use it for the rest of my life than have to buy another one.

Chuckt wrote:

Garth wrote:If it's everything it says it is, and it lasts, it sure looks like a good deal.

Thank you. What I learned from an Engineer (Chris) is that while it is a good unit, the potentiometer can build up dust or dirt over the years and create noise so the voltage could be set at one voltage and jump up to another voltage before it settles down.

That's true of any of the inexpensive test equipment, but after years of use, when this starts to happen, you can just remove the power supply's cover and spray some contact cleaner into the pot and work it around, and you're ready for a few more years, and so on. One of my oscilloscopes on my workbench now needs that badly, and I keep putting it off because I have other equipment stacked on it and so on, and it'll be a pain to get out and get it open. There are pots that won't need it, but they're too expensive to put in a unit like this.

I'm looking for a digital or would that be linear power supply?

Linear power supplies can still have digital controls, but depending on how they do it (to make it so they can sell it so cheap), the granularity might not be as fine as you want. Switching supplies are usually not as good for multi-purpose workbench applications since their output is not as quiet and the noise can cause problems in sensitive circuits, and they may not be able to maintain regulation over the wide range of voltages and load currents required for this application.

Are there any other power supplies for a little more that might be better? I might consider them.
I'd rather buy the right tool and use it for the rest of my life than have to buy another one.

I agree with the long-life concept. The power supply I use most is made by Global Specialties. I've had it for probably 25 years and they still sell it (although with minor stylistic changes), and it does need the pots sprayed again but it has performed way beyond the specifications.