Reddit mentions: The best power supplies for labs

> Answer for New to electronics, where to start?

Everybody learns differently. Some people are theoretical learners, while others are physical learners who need to touch things with their hands to learn anything. And others still are some hybrid between the two. As such, it is very difficult to answer the question "where to start", because there is no one-size fits all solution.

Further complicating the issue is the issue of budget. Not just monetary investment, but time investment as well. No doubt, the best education possible is to simply go to a multi-year university and dedicated multiple years of your life to the trade, but this is more than the typical hobbyist can afford.

Assuming infinite time and money, the ideal learning environment is a lab environment surrounded by high-end, precise and accurate equipment (often costing in the thousands of dollars) with which you can measure, test, and experiment to the heart's desire. For example, accurate variable power supplies that can operate in voltage-mode or current-mode... signal generators to create square, triangle, and sine waves, and a high-end, very accurate Tektronix Oscilloscope so that you can actually see the voltages and currents as they happen. Indeed, this is what your typical lab environment inside a college would be like.

Dedicate yourself to graduate-level college subjects, and you will also get you access to very high-end material, such as scanning electron microscopes, clean-rooms, VLSI integrated circuits, FPGAs and custom PCBs to tie it all together. Mastery of these subjects, aided with state-of-the-art software for simulations will put you into the upper-echleons of world-class electrical engineering.

But learning how to use such complicated equipment is itself a learning curve that takes not only money... but time as well. There are plenty of hobby-level electronics users who make due with both simpler and cheaper equipment.

AA or 9V Batteries provide cheap sources of nearly ideal voltage sources (at least, while the batteries have juice in them). Digital Multimeters can be bought as cheaply as $20... although most people will recommend spending around $100 for a solid precise and accurate multimeter (better accuracy costs more money). Add on $50 to $100 for a breadboard and some typical components (a light bulb, a motor, resistors, capacitors, and some basic chips like a 555 timer or an Op-Amp, and wires to hook it all together), and you'll be well on your way to learning electronics.

Finally, there's the issue of subject material. There are complicated analog components, like building power-supplies, or radios... and then there are complicated digital components like logic and even computers. The two worlds require different math to understand (Discrete mathematics for Digital, Calc3 / Differential Equations for Analog).

There are also software packages to help students learn on the cheap. There are programs that are free for hobbyists, like LTSpice for simulations or Eagle for schematic drawings / PCB layout.

--------

I'm sorry for the long-winded answer, but this is a deep subject with many valid paths forward. This all comes down to the following:

1. You need to learn some degree of theory to get started.
   
   
2. You can accelerate and/or augment your theoretical learning with software tools such as PSpice. Its a lot cheaper and faster to simulate an effect rather than to actually use real components.
   
   
3. You need physical equipment. Software will never replicate the smell of burning components when that resistor catches on fire for the first time. Some things can only be learned when working in the lab.
   
   Theory
   ============
   
   Here are a list of recommended books:
   (Someone else: make a list of good beginner books, I dunno of any).
   
   There are also free online courses:
   
   

• MIT's 6.002: This is the first course taught at MIT, and all of the video lectures, exams, and class material has been posted online for free.
  
  
• All About Circuits: This messy webpage actually holds a lot of good information about circuits and electronics. I find that paid books are better, but if you don't want to spend any money, this is a very complete reference.
  
  Software
  ===========
  
  The primary software you need as a beginner is a "SPICE" simulator. You can place components like resistors, capacitors and inductors and the software will simulate the components.
  
  
• Partsim is a free website that can simulate your basic electrical components.
  
  
• LTspice: Linear Technology wants you to buy their stuff, so they made a free program that accurately simulates their chips. Can't argue with the results or this marketing scheme though, free software is extremely good and useful for the beginner.
  
  Tools and Hardware
  ===========
  
  
• Uggghhhh. I'm tired. Work in progress, will continue writing later.
  
  
  WORK IN PROGRESS
  ==============
  
  
• Finish First Draft
  
• Edit down my wordy language to be shorter
  
• Come up with good beginner books (paid books generally are easier to read and are better edited)
  
• Figure out some decent beginner kits: both digital world (something Arduino based with a decent free web-lessons), and analog world (opamps and stuff).
  
• Work out a set of beginner tools, in order of "cost-effectiveness" (Ex: Digital Multimeter, cheap USB Oscilloscope, etc. etc.)

To answer your question yes you will get DC out and you can adjust the voltage with the potentiometer.

As for better options, yes and no. It'll work fine, a commercial product would probably add a lot of filtering and safety circuitry around it but for hobby stuff it'll work perfectly.

Another option if you want something more user friendly is to rectify the 24VAC and feed it into one of These. Expensive but if you're looking for a bench supply type of thing its quite good.

​

How it works (of the top of my head anyway). The big black rectangle is a full bridge rectifier changing the AC to DC, this is smoothed by the first big cap (and normally some smaller ones) this voltage is the "chopped" up into pulses by the chip, this causes the current in the inductor to change. As an inductor resists changes it will try and keep the current constant so output voltage will be (in this case) lower depending on the frequency of the chopping. The diode prevents current flowing backwards into the input side of the circuit. The output voltage is then smoothed by the second big cap (again normally some smaller ones) then you have the output voltage. This output is controlled via feedback of the output voltage into the IC, the potentiometer controls the voltage the IC sees and thus the voltage on the output.

Do you think there's a market for this sort of thing? Like, if you were to sell the equivalent for $75, do you think there's enough people that would buy it to make it worth the time? Thinking about whether it would be worth the effort to make up a little version of this :)

I would be curious to see what the chip # is, as well as the 3-pin part on the side (under the grey heatsink putty).

I have a feeling what that active circuitry does is actually act as a constant current regulator to charge up the caps. The problem you will have with so much capacitance is getting a massive inrush when you first connect the power supply. Ie, the caps will look like you shorted the power supply until they reach the operating voltage. The power supply probably won't like that.

So, having said that, to answer your question about capacitance: You can try experimenting.
To start with, it looks like they have a 2200uF cap + 6 of whatever those other things are (still assuming they're flat pack caps, but they could be something else). My feeling is that they're probably some lower value to deal with some of the higher frequency components.

I would buy a selection of beefy caps, and just start putting them in parallel with the power supply. Make sure they're rated to be at least 16V!

Instead of the constant current circuit, you could have a toggle switch (make sure it's rated to at least 1.5A) in parallel with a 1-ohm power resistor.

When you want to connect power, you have the switch in the open position, then connect the power supply. Wait maybe 10 seconds, then flip the switch to the bypass / shorting position to remove the resistor from the circuit. At that point, you can use the camera.

Something like this:

https://imgur.com/a/5VgBx

EDIT: screwed up on power jack, more like this: https://imgur.com/a/00ujw


EDIT2: You can also buy constant voltage / constant current power supplies. Lab power supplies are an example. They won't care if you short the output; they'll happily limit the current to whatever they're set to. Actually, most wall adapters have a similar "anti-short" protection of some sort built in, so you might be able to get away with not using the switch / resistor trick.

You could buy something like this: https://www.amazon.com/Eventek-KPS305D-Adjustable-Switching-Regulated/dp/B071RNT1CD/ref=sr_1_5?ie=UTF8&qid=1523427142&sr=8-5&keywords=lab+power+supply

Although the theory and understanding of nodes and meshes from circuit theory is important, practical electronics-level knowledge can be found in The Art of Electronics. See genlib, but I suggest to buy it and get some basic electronics kit, a power supply (a proper lab supply with adjustable voltage and current limit [1]) and a breadboard and create the circuits that you're studying, play with the basic devices, and make a project once you get the hang of stringing logical blocks of circuit components together.

I find it fun :)

[1] SOmething like https://www.amazon.com/Adjustable-Eventek-KPS3010D-Switching-Regulated/dp/B073TW8H2S/ref=sr_1_5?keywords=lab+power+supply&qid=1565149853&s=gateway&sr=8-5
It is the same chassis as my current supply, maybe same actual device inside, but I found it for more like $60 a few years back. The key is the ability to set a current limit, so when you hook something up incorrectly the circuit doesn't fry.

You are looking at it the correct way. You want to be pretty exact when it comes to the power supply. Some electronics have more or less tolerance to the power supply being exact than others, so you can’t 100% rule out that you just don’t have the right one. Depending on your budget there’s a couple different things you can do. 1) try to email peavy customer support and tell them the exact model you have and if they can sell a power supply to you or recommend one that would work from their existing parts supply. If you’re lucky, they should be able to send you a power supply for pretty cheap (maybe $10-40 shipped...? Just a guess tho).
2) if you can’t get it from peavy, look for that exact voltage and amperage power supply from any electronics supplier online. If the barrel plug doesn’t exactly fit, splice it onto one that does fit the peavy.
3) the slightly more expensive option, but as you were indicating, you want to know whether or not it’s a power supply issue first. Over the years of investing in electronics, I eventually got a bench tester. This one :bench tester

It allows you to finely dial in whatever voltage and amperage setting you need to properly power your dc circuit. This is a really helpful tool to have and will
Allow you to provide power to any dc electronics that you’re troubleshooting or prototyping. Obviously if you’re trying to just stick to making work what you already have, it might be prohibitively expensive, but In the lifetime of working with electronics, this and a multimeter are invaluable

Wow that is a ludicrous price. Most of us could flatulate a better design. Based on what I see immediately in front of me I would use two of these mk2 3d printer bed plates. Put them in series. https://www.amazon.com/dp/B01HPXA8EC/ref=cm_sw_r_cp_apa_O.vjybW7MW53F then I'd take my shittest power supply set it to 24V and maybe some constant current at 500mA to 1A and see how hit it gets under the aluminum. https://www.amazon.com/dp/B00O8DJ8QC/ref=cm_sw_r_cp_apa_ndwjyb2N27R1A

Best part you dont need a controller cause even that silly $1000 device is only giving you a adjustment pot. Then if your wife changes her mind you can start building a 3D printer.

Go to harbor freight and treat yourself to one of those laser aim non contact thermometers too. You'll marvel at how much money you saved and how even the heat is.

Based on the feedback in the thread (and the fact that I've already modded an ATX power supply), I'm going to buy a bench power supply.

I'll be powering motors and microcontrollers that have different voltage requirements. So, should I get a multichannel power supply? Should I get several single-channel units? Or, should I get a single channel power supply and build my own circuits to step it down for the lower voltage circuitry?

> A cheapie will usually do

There's a significant range of prices: a single channel Rigol or Agilent costs more than a multichannel BK Precision. Likewise, a single channel BK Precision costs more than a multichannel Tekpower. If there's a significant quality difference, I'm fine with paying for it: I'd like to get something that supplies high quality power and is built well. However, I'm sure at some point I'd be paying for features and precision that I don't need.

For instance, the Tekpower TP-3005D-3 looks pretty appealing. This review shows that it's built better than the Mastech HY3005F-3 (EEVblog teardown). There are also plenty of people who seem to be happy with their Mastech and Dr. Meter power supplies. Looking at the chassis for the Tekpower, Mastech, and Dr. Meter 3 channel power supplies, they all appear to either be rebranded versions of the same unit or some of them are knock-offs.

So it looks like the official power supply model is M5849. Looks to be straight 28v output; on the 4 pin power connector 2 pins are +28v and two are -28v.

You could use something like this to power it. Getting a hold of that weird 4 pin connector might be tricky. Being Apple I doubt it was a standard thing you could order from somewhere like digikey; if it is I honestly wouldn't know where to start there.

But for $10 more you could buy the real deal it looks like.

All of that being said the one you linked is untested and quite possibly non-functional. For $100 you can have a tested working one with a power supply. Obviously I don't know your budget or goal but the whole thing seems like a bit of a faff that I'd expect there's an easier/cheaper way to accomplish.

One final note if you do roll your own power supply check it out internally before powering it up. I have a similar 24v "industrial" adapter powering my old 30" cinema display and the build quality's about what you'd expect for $20-30; there were some things that needed tightened down that could have caused some issues if I hadn't checked it out first.

While I don't recommend bottom of the barrel, You hit the "monster-cable-better-digital-signal-quality" snake oil pretty quick in the PSU market.

Unless your overclocking and need super stable power at razor thin margins. Consumer gear can easily handle anything that's properly in spec.

More than about 100 bucks though and you could buy an actual Bench power supply

There's a ton of them out there, but something like this is fine. If you are trying to go really cheap, then a battery charger is just fine. Just avoid newer ones because they usually come with an automatic shut off that won't work with your solution. There are a lot of electrolysis tutorials, but just knock any flaking paint off after you're satisfied and prime and paint. You might consider a self etching primer with a rust inhibitor if it's going back outside.

I use a regulated power supply. Similar to this:

https://www.amazon.com/dp/B071RNT1CD/ref=cm_sw_r_cp_api_i_69N1DbPAKQTZV

You want to make sure to use DC (Direct Current) and not an AC(Alternating Current. The regulated power supply lets you adjust the current and give more control. I use 5VDC for Carbon Steels and 12-25VDC for Stainless. I put the Positive on they item I want to etch and the Negative on a bolt with rubber bands holding a cotton balls on it. I use just salt water. Always keep it moving around when you are etching. I finish with a brass wire wheel to clean up. I get my stencils made from a local vinyl shop. They work great for me.

After a lot of looking around I picked up a Korad KA3005D for ~$120USD and free shipping.

Will supply up to 5A at 30VDC; reviews all say it regulates the power well, doesn't have any crazy overshoot when turning off/on, little voltage ripple; comes with leads; and has a separate output on/off toggle so you don't need to disconnect the leads to adjust power or anything; over-current protection; digital display so you can enter your values with precision.

Probably a reason it's one of half a dozen models listed as recommended on the wiki.

Bit more than you probaly want to spend, but I've had good luck with this one for about $90. Korad kd3005D

I was really hoping that was the case, but I swapped the cheapo power supply with one of these:

https://www.amazon.com/gp/product/B071RNT1CD/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

And The same thing happens. I've got the Current dialed all the way, with the voltage at 5.5 (same as the power supply that works). It shows a 1.4 Amp draw, which the supply should be more than able to handle. Same deal though, servo runs to zero. Still works fine using the dedicated 5v supply putting out 5.5v.

Say I'm building a mini ECU simulator. I need to provide 12v @ 5A DC over OBD-II. What's the best way to do this, with something like this: https://www.amazon.com/Tekpower-TP3005T-Variable-Linear-Alligator/dp/B00ZBCLJSY/ref=zg_bs_318022011_1?_encoding=UTF8&psc=1&refRID=P1DKJT59MMVX11ZWARXM ?

Here is the one that I use. It's heavy, but works pretty well for me.

I picked up the one in the picture off of Amazon for $70. It can push up to 30V/5A so it’s been great so far for anything I’ve needed to power.

https://www.amazon.com/dp/B078WT94S7?ref=yo_pop_ma_swf

I meant the ELV DPS 7000 that he shows in the beginning of the video, not the computer PSU that he hacks into. Compared to something like this, the ELV looks like it's straight off the set of some 70's sci-fi flick.

This one seems to have good ratings. There are probably a couple dozen similar ones out there that are just as good.

https://smile.amazon.com/Tekpower-TP3005T-Variable-Linear-Alligator/dp/B00ZBCLJSY/ref=sr_1_3?ie=UTF8&qid=1541456044&sr=8-3&keywords=lab+power+supply

There are also multiple-output ones too -- it all depends on what you plan to do.

EDIT: After reading some of the reviews, do look at what they say about the way this one sets up the voltage. It might not remember the voltage setting on power-up, so you may have to set it each time before you connect it.

For scope: get a used tek on craigslist

For function generator: this kit

For iron: Hakko 888

You probably want a bench PSU as well: Korad 3005D

You need safety gear too!

• Respirator - half face with P100 filters
  
  
• Goggles
  
  
• Gloves
  
  Don't forget blank PCBs and etchant, breadboard, jumper wires, etc.

I can't respect a video where someone shrinks their tubing with a lighter. Get a heat gun you savage!

Personally I started to make a bench supply out of an old ATX power supply (though I was just going to provide 12 and 5v outputs and deal with stepping it down externally) when I came across a good deal on one of the cheapies like this. A project is nice but I had other things I wanted to get to where this would be helpful.

A bench power supply is just that. A power supply for your bench. It has an adjustable voltage output (the one I will be linking ranges from 0 volts to 30 volts) & an adjustable current limit (maximum amount of current it can provide before it lowers voltage to compensate).

It is really an essential tool for all sorts of troubleshooting and testing.

This is one of the first ones I found on Amazon. Power supply 0-30v

I would recommend doing some research on bench power supplies and making your own well informed decision on what is right for you.

You would be much better off with something like this:

http://www.amazon.com/KORAD-KD3005D-Precision-Adjustable-Regulated/dp/B00FPU6G4E

The best part to me is that I could order one on amazon for $30.

Bench power supply is one of the best purchases I've ever made since getting into this hobby.

It's this one. I got it early this year. It's worked great for me.

You can control fans and some pumps with a potentiometer (variable resistor) spliced into the power wire but I would be concerned with it heating up. I have an old one I can give you info on when I get home but there's also this regulator which would give you a nice display and adjustment point.

Ill take a look when I get home again about behind the transformer. The fuse (more like a breaker) did blow at one point, which i was able to reset, but it did not last long. When it "blew" the second time, there was a definitive odor... Would something like this -

http://www.amazon.com/gp/product/B0002DVEZA/ref=s9_simh_gw_p60_d0_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0BE394475YHEAV1APH2G&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

or

http://www.amazon.com/gp/product/B000RO8J98/ref=s9_simh_gw_p60_d0_i2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0BE394475YHEAV1APH2G&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

be able to run the motor?

here's a popular one on amazon. three outputs, 30v 5A:

http://www.amazon.com/gp/aw/d/B004ISD7T6

I know theres not much love for the cheap import stuff in this thread, but i have this one, and its been verrry good to me for the price:

Tekpower TP3005T Variable Linear DC Power Supply, 0-30V @ 0-5A with Alligator Test Leads (110V Input) https://www.amazon.com/dp/B00ZBCLJSY/ref=cm_sw_r_cp_api_S9nYBb4J9SGFW

This one had good reviews when I bought it and hasn't burned down my house in the last 11 months! $80, if that's "inexpensive" to you.

You can probably get that model cheaper somewhere else, BTW. I just linked to the first place I could find it.

There are also even less expensive choices that are still quite good quality, though you won't get quite as much current. For example, buy two of these: http://www.amazon.com/KORAD-KD3005D-Precision-Adjustable-Regulated/dp/B00FPU6G4E/ref=pd_cp_hi_0/190-7609066-1491003

You just want a controllable constant-current-constant-voltage power supply. Buy this.

Your solenoids, like all DC loads, have some Current vs Voltage curve, that they have to obey. For the simplest load possible, a 1-ohm resistor, that curve is Current = Voltage / 1 Ohm. Solenoids might have a nonlinear curve. But they simply can't operate off of the curve. All you get to do, as the operator, is choose where on the curve to be. You can apply whatever voltage you want, and the curve will dictate what current flows. Or you can choose what current you want, and apply the voltage that gives you that current. The device that you need to do both of those things is a constant-current-constant-voltage power supply.

What you've been told ("the voltage needs to remain at the same level whereas changing the amps with move the spool") is probably just a simplification of the fact that the current-voltage curve in the region of interest has a very high slope - so only tiny changes in voltage are needed to produce large changes in current. Or, put another way, the desired change in current will only require a tiny voltage change. Or they were just wrong, and misunderstand it themselves.

I got this thing

it's effectively a toy. Doesn't have adjustable current controls, just variable 0-15 volts. At the time I just needed something to probe some lipo battery cells in a surface power cover and and recharge them.

To be frank, I'd just get an adjustable bench power supply like this: https://www.amazon.ca/Adjustable-Switching-Regulated-Alligator-Spectrophotometer/dp/B07GCJP6B1/ref=sr_1_19?crid=2TCRYQFCCZ6PO&keywords=bench+power+supply&qid=1573485107&sprefix=Bench+power%2Caps%2C182&sr=8-19

Set it up to constant current, then hook it up.

This way you get feedback on voltage, current, and if you change setups (or want to do one battery at a time) you can.

I bought this. It has served me well through circuits and electronics classes. You can find a combo beadboard/components kit on Amazon.

I've been happy with this power supply I bought off Amazon. I looked around for a manual battery charger, but didn't find one.

If you buy less than a $300 power supply and it blows up $10,000 of hardware because its output regulation is as shitty as this one's, then that's kind of false economy, isn't it? This supply's radiated EMI is also shit, like 14dBuV over the Class B limits. That is junk.

The output regulation on the one I had drifted multiple volts over six hours. Don't use this POS for work without an overvoltage zener, a fuse, an inline resistor, and a pi filter after it, or you will be risking the success of your project.

And if its shittiness costs you more than a day, that is at least $200 in just loaded wages alone for you, to say nothing of other peoples' time you're going to waste. (If something wastes a day of my time, it costs my employer or client more like $1000.)

And the DARPA grants I've worked on do pay for >$300 power supplies.

At the very very least get this one as you have at least a chance at it not being utter shit (as in, smoking itself) and it's USB programmable. EEVblog seemed to like it.



A good power supply is the bedrock that everything else rests on that you build. With a bad one like this Arksen, you're building in a swamp.

There are no issues with plastic containers- I can only get melting when I try to do it on purpose.

No, these are much higher quality LEDs than found in UFOs and will give off roughly twice the light per watt.

In a five gallon bucket with foil sides and the COB eight inches from the plant, with a Bridgelux Vero 18 at about 10 watts your plants will be at about 500 uMol/m2/sec of light (35,000 lux). This is a really good level for veging.

With 20 watts on the Vero 18 you'll be saturating your plant at 1000 uMol/m2/sec (about 70,000 lux). This is perfect for flowering. You can drive the LED harder but there will be rapid decreasing gains.


If you want to know about building COB grow lights from a competent person then you should check out growmau5's YouTube page. Outside the professional arena and even in it, this person likely knows more about COB LED grow light design than anyone else.

https://www.youtube.com/channel/UCPSwmwj8ZLXObtBJmz-76rw

I often use lab power supplies as variable LED drivers. I bought two of these recently to replace some others. If you do much work with LEDs then these sort of power supplies are real time savers.

https://www.amazon.com/gp/product/B00ZBCLJSY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

look up: Vero 18 3500K CRI 80 gen 7 (the Vero 29 costs three times as much but will be even more efficient)

https://www.digikey.com/product-detail/en/bridgelux/BXRC-35E4000-D-73/976-1421-ND/6152431

edit- corrected "3800K" mistake

You need the right voltage charger. Whenever I deal with any battery banks that are screwy voltages, I usually use my 4A lab bench power supply (Tektronics PS280) as a stand-in. Something like this or this would do just as well.

Bought one of these this year and like it a lot for home use: http://www.amazon.com/gp/product/B0084JFWNY

like this?

https://www.amazon.com/Eventek-KPS305D-Adjustable-Switching-Regulated/dp/B071RNT1CD

I've never handled ones that looked like that. I'm more familiar with this type;

http://www.amazon.com/Tekpower-TP3005T-Variable-Linear-Supply/dp/B00ZBCLJSY/ref=sr_1_4?ie=UTF8&qid=1463512378&sr=8-4&keywords=5a+dc+power+supply

Well, you can always try the H bridge using the 6V output and see what happens. But power supplies are not very expensive:

https://www.amazon.com/YaeCCC-Variable-Adjustable-Bench-Supply/dp/B074C86DSY/ref=sr_1_1_sspa?s=industrial&ie=UTF8&qid=1526155783&sr=1-1-spons&keywords=30v+5a+lab+power+supply&psc=1

Gesswein is Canadian, as is Caswell.

Not knowing where you are, I suggest you searching for a jeweller's supply shop.

In Vancouver there is Lacy West.

I'm pretty sure Rio Grande and/or Ottofrei will ship those chemicals to Canada.

Edited to add, I purchased this power supply from Amazon.com with no problems.

Beep boop you want a power supply: https://www.amazon.com/Precision-0-100V-Adjustable-Digital-Regulated/dp/B01831QRFY

i haven’t bought one yet😂 ill tell you how it is around December 5th

https://www.amazon.com/dp/B07512KQDW/ref=cm_sw_r_cp_api_i_o7a4DbKQXW8PN

Read Reviews

https://www.amazon.com/gp/product/B071RNT1CD/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

See that. Changed it to "power". A simpler supply? Any examples? I found this one too: https://www.amazon.com/Tekpower-TP3005T-Variable-Linear-Supply/dp/B00ZBCLJSY/ref=sr_1_3?s=industrial&ie=UTF8&qid=1487919457&sr=1-3

A cheap liner bench power supply.

https://www.amazon.com/Flexzion-Compact-Power-Supply-15V/dp/B0146K50LI/

Though I'd spend $20 more, which is why I said almost: http://www.mastechpowersupply.com/volteq-regulated-variable-dc-power-supply-hy1503d-15v-3a.html

Would this work? It seems to havethe same specs, but half the price?

Crafty!! I've been looking at 0-120v dc power supplies. I Might try this one from AMAZON

This is not a recommendation, just some examples of what exists on the low end for bench supplies (off-the-shelf in the US):

KORAD KD3005D Precision Variable Adjustable 30V, 5A DC Linear Power Supply

That's a single output channel for $85.

I have something very similar to Triple Linear Variable DC Power Supply, Adjustable 30V/5A. There are many lookalikes. That's two adjustable channels, plus a fixed 5V (which I never use) for $180.

When working with a cheap supply, I:

• don't leave it on unattended or overnight
  
• always disconnect the load before turning the power switch on or off.

I've got this one, works well enough, no complaints. Plenty of power for charging up some lithium cells.

Tekpower TP3005T Variable Linear DC Power Supply, 0 - 30V @ 0 - 5A with Alligator Cable and Power Cord,Upgraded TP3005D,HY3005D, Mastech

https://www.amazon.com/dp/B00ZBCLJSY/ref=cm_sw_r_cp_api_JAxJyb86T5GFC