Author Topic: Best 80-110 dollar power supply?  (Read 6125 times)

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Offline perfect_disturbance

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Best 80-110 dollar power supply?
« on: February 14, 2013, 12:13:47 am »
So what is everyone's opinion? I looked over a bunch of power supply topics but most are just about the pros and cons of individual supplies. Which of the low cost supplies are best for a beginner that is still tinkering in a wide area of electronics but is mostly working with micros.
 

Offline Jon Chandler

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Re: Best 80-110 dollar power supply?
« Reply #1 on: February 14, 2013, 02:42:21 am »
A 5 volt "wall wart" salvaged from a cell phone or other piece of electronics can go a long way with micros.
 

Offline c4757p

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Re: Best 80-110 dollar power supply?
« Reply #2 on: February 14, 2013, 02:55:13 am »
Yep. This is my recommendation as well if you're going to be working primarily with micros. Maybe find a 9V or 12V one for the occasional analog stuff, or even a higher voltage one plus a couple LM317s. If you're going to dig into analog more, I highly recommend finding a used power supply - you can get a lot more quality for the same cost. A lot of them were built like tanks. I recently picked up a Power Designs TP343A for $90 incl. shipping and the thing is pretty much indestructible. Most are no more than a pile of pretty generic transistors and op amps as well, so easy to repair if there's anything wrong with them.
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Offline houdini

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Re: Best 80-110 dollar power supply?
« Reply #3 on: February 14, 2013, 03:50:20 am »
Atx for different voltages.  A bunch of servers power supplys in series for 12xnV at 75-100amps you can use regulators and such after that.
 

Offline c4757p

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Re: Best 80-110 dollar power supply?
« Reply #4 on: February 14, 2013, 03:54:48 am »
An ATX supply as a lab supply is a recipe for fire. They're really useful for some things - where else can you get such a high current supply for as cheap? - but be careful.
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Offline houdini

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Re: Best 80-110 dollar power supply?
« Reply #5 on: February 14, 2013, 04:21:26 am »
I have only had server supply's cause fire never an atx and even that was a mosfet blowing wires usually just melt into an acrid plume of smoke.
 

Offline smashedProton

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Re: Best 80-110 dollar power supply?
« Reply #6 on: February 14, 2013, 04:33:28 am »
make your own!  It's a fun and rewarding project.  You can use an atx power supply with extra emi filtering, load switches and indicators, lm317 regulator, and cc circuitry.  Good stuff  :-+
http://www.garrettbaldwin.com/

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Offline perfect_disturbance

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Re: Best 80-110 dollar power supply?
« Reply #7 on: February 14, 2013, 06:04:43 am »
So its not even worth looking at a lab supply in the 80-110 range?
 

Offline mariush

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Re: Best 80-110 dollar power supply?
« Reply #8 on: February 14, 2013, 01:46:30 pm »
An 80-110$ is kind of low.

You're not going to get a linear power supply for that money, one that's worth buying, and linear power supplies are much better as they have less voltage ripple and often can be adjusted more precisely (10 turn pots etc)

So you're looking at smps power supplies... and in that category there's nothing special popping out. There are some power supplies as low as $60 dollars but pretty much they're all the same, ok but not great.

There's plenty of linear power supply designs out there... you can buy a 2x18v 6-8a transformer for around 20-25$, opams, resistors, capacitors, potentiometers, transistors etc cost you about 30-40$ including the heatsink for the pass transistor(s), pcb costs you about 10-15$ if you design it yourself and send it to some pooling service... so it's a bit hard but you CAN make your own linear power supply for under 100$, that's about as good as a $150-200 one.

 

Offline UPI

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Re: Best 80-110 dollar power supply?
« Reply #9 on: February 14, 2013, 02:22:48 pm »
The Korad KA3005P is very good for $105. Yes, it has a some overshoot, user interface idiosyncrasies and the I/O is clunky, but otherwise it is a good deal and does most jobs just fine.

http://www.amazon.com/KORAD-KA3005P-Programmable-Precision-Adjustable/dp/B0085QLNFM/ref=cm_cr_pr_product_top



I have incorporated it into an auto calibration jig with a Fluke 45 to read the actual voltage and and it does the job well.

 

Offline perfect_disturbance

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Re: Best 80-110 dollar power supply?
« Reply #10 on: February 14, 2013, 03:57:10 pm »
I looked at the Korad. But most of the posts out there for the Korad are pretty negative is it a decent supply?
 

Offline c4757p

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Re: Best 80-110 dollar power supply?
« Reply #11 on: February 14, 2013, 04:04:09 pm »
Many of the posts are going to be negative for anything in this price range. It's a $100 power supply, it's not going to impress anyone.
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Offline UPI

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Re: Best 80-110 dollar power supply?
« Reply #12 on: February 14, 2013, 04:19:03 pm »
The ripple is relatively low, it can be adjusted in 10mV/1mA steps, works in either CC or CV mode, can be controlled over USB/Serial, puts out 5A and is dirt cheap.

Most of the negative reviews were addressed with modifications from the manufacturer.

I think you will be happy with it as long as you know its limits.
 

Offline saturation

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Re: Best 80-110 dollar power supply?
« Reply #13 on: February 14, 2013, 04:31:54 pm »
You can easily get a quality lab grade used linear supply for under $50, many of the Power Designs precision supply sell in your range.  See the thread archived in eevblog.

So its not even worth looking at a lab supply in the 80-110 range?
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Offline UPI

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Re: Best 80-110 dollar power supply?
« Reply #14 on: February 14, 2013, 04:54:48 pm »
I guess it comes down to whether you want to control it externally, how many outputs you need and at what current.

A cheap linear programmable supply was the main requirement for my application. It will be handy for other uses as well.
 

Offline rsjsouza

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Re: Best 80-110 dollar power supply?
« Reply #15 on: February 14, 2013, 05:06:58 pm »
You're not going to get a linear power supply for that money, one that's worth buying, and linear power supplies are much better as they have less voltage ripple and often can be adjusted more precisely (10 turn pots etc)
I agree. However, since you are in the US your options increase. If you feel brave tinkering with "brand new" equipment, you can get an el-cheapo from eBay and modify it to improve the regulation, noise, safety, etc.

Of course, you can always start with a really well-designed but used one like this one - this gives you a lot more confidence in case you prefer to focus in your own circuits and not on the power supply itself.  :)
« Last Edit: February 14, 2013, 05:09:11 pm by rsjsouza »
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Offline Nirios

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Re: Best 80-110 dollar power supply?
« Reply #16 on: February 14, 2013, 05:41:28 pm »
Of course, you can always start with a really well-designed but used one like this one - this gives you a lot more confidence in case you prefer to focus in your own circuits and not on the power supply itself.  :)

+1 for old HP supplies.  They are great, the only negative is that they can be very heavy and easily damaged in shipping if not packed properly.  A 6227B I ordered from ebay was damaged in shipping.  The internals  of the supply are made of aluminum and can bend if dropped.
 

Offline T4P

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Re: Best 80-110 dollar power supply?
« Reply #17 on: February 14, 2013, 06:13:28 pm »
+1 for old HP supplies but too bad the only HP PSUs i can get IN MY TOWN are (Bloody hell, the last time i talked about the VC8145 i got people saying it's more worth it buying a HP old DMM without looking at where i am, shipping a HP DMM costs a bomb and by the time it gets here it's probably thrice the cost of it)
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Offline smashedProton

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Re: Best 80-110 dollar power supply?
« Reply #18 on: February 15, 2013, 06:48:51 pm »
With the projects that I have been doing, I really need a dual tracking supply for opamps And things.  So what is the good recourse for making/buying them.
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Offline MikeK

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Re: Best 80-110 dollar power supply?
« Reply #19 on: February 15, 2013, 07:00:58 pm »
EPE mag had a dual tracking supply project in the June/July issues for last year.  It was a project from Silicon Chip mag.  I'm interested in building it, since it looks like I have almost all the parts.
 

Offline reagle

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Re: Best 80-110 dollar power supply?
« Reply #20 on: February 16, 2013, 04:11:50 am »
Look at HP E36xx series. Can be had for about $90-$100, and are very nicely built. I just bought several for work lab. Takes a bit of patience and properly setup ebay filters :)

Online NiHaoMike

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Re: Best 80-110 dollar power supply?
« Reply #21 on: February 16, 2013, 02:35:31 pm »
An ATX supply as a lab supply is a recipe for fire. They're really useful for some things - where else can you get such a high current supply for as cheap? - but be careful.
Add in line PTC fuses or circuit breakers. A car light bulb would work as well but might drop too much voltage at normal currents. Some ATX supplies also need a minimum load to operate (a car light bulb works well for that) but the latest ones should be fine at no load.
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