# Recommenced DC Power Supply for Breadboarding

#### djsfantasi

Joined Apr 11, 2010
7,700
Hi!

To save some time, would like to review recommendations for a DC power supply, 0-24V constant voltage supply or 0-5A constant current supply. Would accept 0-12V or 0-2A...

I’ve been looking and have a couple of candidates, but don’t think they’re right for me.

Any suggestions?

#### SamR

Joined Mar 19, 2019
3,413
Tariffs.

Bob

#### djsfantasi

Joined Apr 11, 2010
7,700
It depends on what you want to do.
When working on opamp circuits, a dual powersupply can be welcome.
When working on digital chips a 5 Volts or 3.3 Volts powersupply will do.

Bertus
Never considered that option. Thanks for bringing it up. Most of the designs I’ve been working on are related to device control by a μP. But I’ve been dabbling in audio recently. True audio, not half wave audio.

#### djsfantasi

Joined Apr 11, 2010
7,700
Tariffs.

Bob
I noticed that! Just in the time between our replies.

#### Hop

Joined Feb 14, 2013
8
There are dozens of good bench supplies available from online retailers such as Amazon, Circuit Specialists, eBay. Expect to spend less than a hundred bux for a voltage- and current-metered power supply with your specs. If I were to suggest a caveat, it would be to avoid switching power supplies for bench prototyping in favor of linear-regulated power supplies.

You might also want to consider building your own bench power supply. You won't save any money doing that, but you will learn a lot along the way. And after all is said and done, it will probably be built exactly to your satisfaction without compromises. That said, consider linear regulation versus switch-mode power supplies.

Linear regulation is very inefficient, but it is also electrically very quiet with very little electrical noise present on the output. Switch-mode power supplies (SMPS) are much more efficient, but by their nature switching noise will be present on their output, and this noise must be removed or suppressed by good filtering. Leave that chore to your final design to avoid problems during prototyping.

If you need the increased efficiency, or a smaller power supply footprint, which you just might if your project is a portable battery-operated design, by all means feel free to use a switch-mode power supply to achieve your goals. However, by using a linear-regulated power supply during prototyping you eliminate a possible source of noise that could interfere with design and testing of your project.

Here at home, I do most of my prototyping with three-terminal linear regulators connected to wall-wart DC power supplies. Some of my projects do require more voltage and/or more current, so I drag out a Variac controlled brute-force power supply that I have constructed for that purpose. For really low-noise DC power I use a block of series-connected D-size alkaline cells. I will admit that I lust for a sleek bench supply, but being an old analog engineer I want it to have variable, tracking, bi-polar outputs of up to ±30 VDC @ 5 A (or more). The cost of one of those would be waay beyond my retirement budget, but maybe I can find enuf parts in my junque box to build one... someday.

#### cmartinez

Joined Jan 17, 2007
7,336

#### jpanhalt

Joined Jan 18, 2008
11,088
If your reason for CC is a potential short circuit, I make do with constant voltage and an appropriate resistor (usually 100 Ω).

#### djsfantasi

Joined Apr 11, 2010
7,700
If your reason for CC is a potential short circuit, I make do with constant voltage and an appropriate resistor (usually 100 Ω).
That’s the primary reason, particularly when testing new designs.

#### djsfantasi

Joined Apr 11, 2010
7,700
I’ve seen those, but they appear to be fixed outputs. Unless I misread the specs, I’d have to add a variable voltage circuit and meters.

#### cmartinez

Joined Jan 17, 2007
7,336
I’ve seen those, but they appear to be fixed outputs. Unless I misread the specs, I’d have to add a variable voltage circuit and meters.
They do have variable voltage output SPSU with voltage and current displays. Let me see if I can find one for you.

#### cmartinez

Joined Jan 17, 2007
7,336

#### djsfantasi

Joined Apr 11, 2010
7,700
Wow, thanks...

I probably could have found those myself, but I’ve been ill since 7/4 and not thinking clearly. Finally, my doc appointment is tomorrow.

#### SamR

Joined Mar 19, 2019
3,413
That’s the primary reason, particularly when testing new designs.
I have never had my Korad trip and usually keep the current limiter down around 100mA. However, I also use a mains supplied w/ GFI 120/12/6 AC1500mA XFMR that I seem to need a new 1A slo-blow fuse for every time I play with it. The Korad is the goto unless I'm playing with rectifying or when I need a 2nd V source that I provide with a LM317 3-24VDC adjustable module I built to use with the XFMR.

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#### narkeleptk

Joined Mar 11, 2019
524

That first one is nice but the shipping kills it.
I love ali and all for many things but ebay is superior for faster shipping and its easy return policy that heavily sides with buyers. For something like this I think you'd be better off finding it on ebay, amazon or walmart.com (its like amazon, not the brick & mortar stores) even if the price is a few dollars more. Most of the best ali sellers are on ebay anyway and many have state side warehouses so shipping is still fast.

#### SamR

Joined Mar 19, 2019
3,413
That first one is nice but the shipping kills it
Yeah I went to Ali first and was where I bought mine, but their prices are up compared to the same thing on eBay now...