Adjustable DC power supply

Thread Starter

AKnogood

Joined Nov 21, 2013
19
Do you guys have an adjustable DC power supply for your home projects? Did you buy or build one?

I was looking at these 2 models on Ebay and would like to know what you think:

Model 1
Model 2

Or would you have any other models to suggest? Thanks!
 

takao21203

Joined Apr 28, 2012
3,702
I built a 60V, 10 Amps supply (peak 100V at lower currents, inrush current much higher).

Without the supply transformer, for about 30 dollars or 40 dollars (it needs cooling fans, a 12V AUX supply, heavy cables, good capacitors, even a heatsink for the rectifier).

TL494 + large VGA cooler + 2 large toroid coils.

I tested a welding transformer and a big toroid as transformers.
I have done a permanent test for 3 months.

The MOSFET can latch at the upper end, but is exchangeable with a PNP.

It is not short circuit proof this would mean slightly higher cost.
 

ScottWang

Joined Aug 23, 2012
7,397
The Mode 2 would be better, because the voltage of mode 1 is too less, but that's depends on what do you do for your experiment, if you say something about what you need to do, maybe it's more easier to give you the suggestion.

I bought the kits from the begining that I started to learn the EE, and I also built the very simple power and like this Two 4 kinds ±5~15V fixed power, it's easy to use, this power can't adjust the voltage, but I have some others can.
 

takao21203

Joined Apr 28, 2012
3,702
Laptop power supply + hacked 12v/35v booster PCB (80 volts are possible with different MOSFET/flyback diode + high voltage capacitor).

It is cheap, useful when you don't need current adjustment (most circuits or real world applications don't have a current regulated supply, except flat panels, TV sets and the like).

I mean it is not needed all to often except for physics lessons in college (opinion). I was always able to do without it.

If you want to regulate currents, it is almost always only smaller currents.
 

#12

Joined Nov 30, 2010
18,224
For most of us, building a power supply is child's play, but two of the "Model 1" supplies would do most of my work, and can not be had for a better price, even if you build them yourself.

I'm serious. If I need 400 VDC, I have a rig for that. If I need 10 amps at 0V to 15 volts, I have a rig for that. +/- 15 with both voltage and current adjustable does more than 90% of what I need.
 

ErnieM

Joined Apr 24, 2011
8,377
My favorite supply gives me 5V at a fwe amps, and a 30 V +/- supply at an amp perhaps. All are voltage adjustable with a max current limit set. I've got three I believe, one is even programmable (IEEE-488).

That said, in the past year I've used my 9V wall wart the most. My point is you will never go wrong with a quality lab supply you can depend on 100%
 

takao21203

Joined Apr 28, 2012
3,702
yes but if you relocate, you need to dump it as ewaste or as donation somewhere, or to pay a lot of $$$ for transportation costs.

If you are a student and then have accumulated a lot of gear.

These metal shells can last 1000s of years so if you intend to move, add the cost of disposing or transportation.

I made some experiments with power electronics but the welding transformer was easy to get rid of- as good as new.

It is not guaranteed you can get rid of a big power supply quick somewhere out there.

Still having a bag with loads of cables here. It's quite hard to carry through the airport I guess.
 

takao21203

Joined Apr 28, 2012
3,702
I wonder who takao is talking to...:confused:
Do you guys have an adjustable DC power supply for your home projects? Did you buy or build one?

I have been ridiculed by maybe 50 power supplies, wall adapters, and more than 100 cables all incompatible, just within a few years.

I saw (at a workshop) bags full of old wall adapters and power supplies, really loads of them.

I could even post a picture from Ghana where you see people actually dismantling the transformers.

I have an habit to write my opinion in support of a greater cause.

So here is the counter question to OP:

How long do you plan to keep the power supply?
Do you need it immediately for a purpose?
Will you need a different one soon?

Most my experiments can run from USB or batteries or a laptop adapter.
 

Dr.killjoy

Joined Apr 28, 2013
1,196
For what it came down to was price .. I could buy a almost brand new 30V 3amp power that works and has safety features built in for alot cheaper than I could build one and alot less headaches ... Personal I would buy one and then if you want to build one then go ahead but at least you have a working supply ..
Check out mastech power supplies
 

bountyhunter

Joined Sep 7, 2009
2,512
Do you guys have an adjustable DC power supply for your home projects? Did you buy or build one?

I was looking at these 2 models on Ebay and would like to know what you think:

Model 1
Model 2

Or would you have any other models to suggest? Thanks!
Look good, but you might want to get a dual output unit with lower amperage (like 0-20V, 2A dual) because there are so many cases where you will need dual outputs.

We used these at work:

http://www.ebay.com/itm/Regulated-D...706?pt=LH_DefaultDomain_0&hash=item27db5120fa


similar:

http://www.ebay.com/itm/MASTECH-HY3...328?pt=LH_DefaultDomain_0&hash=item3385fec0d0


A pair of these cost less than $100 and would get most jobs done:

http://www.ebay.com/itm/MASTECH-HY1...221?pt=LH_DefaultDomain_0&hash=item2ecc0b7b9d
 
Last edited:

bountyhunter

Joined Sep 7, 2009
2,512
For what it came down to was price .. I could buy a almost brand new 30V 3amp power that works and has safety features built in for alot cheaper than I could build one and alot less headaches ... Personal I would buy one and then if you want to build one then go ahead but at least you have a working supply ..
Check out mastech power supplies
+1 You can't possibly build for what is available to buy these days.
 
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