Author Topic: Forum Intro, and Bench Power Supply Question.  (Read 2922 times)

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Offline MajorEE

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Forum Intro, and Bench Power Supply Question.
« on: October 09, 2011, 08:13:41 pm »
Greetings EEVBloggers,

I've been watching since the start of the blog, and have been lurking the forum for quite some time now and I hope you don't mind I have a question and am going to Introduce myself.

I'm MajorEE, I'm a licensed Radio Operator (Amateur) have an interest in RF, Power Systems, Digital Design, Communications, and Alternative Energy. I'm also working on C++/Python. I hope to be of some use to some of you in the future as far as your Electronics Projects go!

Some of my "Bigger" Projects lately are a Battery Capacity Logging System, (Soon to be upgraded to a digital current control system to incorporate pulse loads and different discharge profiles), Induction Heater, and a Plasma Arc Speaker.

As far as my question, I want to know some thoughts on a Bench Power Supply, I've looked over the brands and heres what I've found:

I realize there is no "Perfect Supply" and that I will have to sacrifice some things, However I'm very tired of my electronics dying on me or giving me false readings. I would like a nice 0-36 would be great, 0-5A CC, Over Voltage Limit is a huge plus/lockout. Anything higher current and it will probably be a single use item or such like my Induction Heater of which I have a Variac and the parts to build a single voltage, high current supply.

I have a 5v, and a 12v supply, +/- 15v but they don't work as well as I'd like, constantly finding problems with them. They probably just need some care but I'd rather just get an upgrade for now.

  • Mastech - Low Quality, Not very accurate
Quote
I've had several Mastech meters in the past and I'm very unimpressed with the quality, My old Mastech meter throws off the readings by a decent amount while the backlight is active.
  • Extech - Expensive, Not that great, Bad review by an EEVBlogger due to poor construction
Quote
I also have several Extech products and generally I think they suck. The IR Thermometer I have has poor tolerances in the plastic, the trigger feels like a kids toy, and it's very very slow to respond.
  • Atten - Look promising, Concerned with the quality and the warning that it isn't meant to power things for any length of time
  • BK Precision - Expensive, nearly bought one Model 9110
Quote
I've heard BK Precision doesn't really put much effort into their power supplies, found this out today from a post on EEVBlog, any truth to this? The 9110 looks nice but with a price tag of $275-$290 I want a high quality supply that's worth my money.

BK Precision 9110:

  • 0-60v 0-5A 100W Max
  • Load Regulation <0.01% +3mV/+3mA
  • <2mVrms/<5mArms Ripple
  • Display Accuracy 0.05% +10mV/0.1% +2mA

Thoughts? Recommendations? Comments? All Appreciated.

Thanks for your time!

Respectfully,
MajorEE
 

Online IanB

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Re: Forum Intro, and Bench Power Supply Question.
« Reply #1 on: October 09, 2011, 09:24:23 pm »
I recently got the Extech 382260: http://www.extech.com/instruments/product.asp?catid=39&prodid=207

I have not used it a lot yet, but it seems fine so far. It is lightweight and compact, goes up to 5 A and 36 V, has over voltage lockout, has four wire remote voltage sensing, has master/slave capability so you can parallel several units for higher current, has output on/off switch, and the current limit can be set while the output is off.

I like it.
I'm not an EE--what am I doing here?
 

Offline saturation

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Re: Forum Intro, and Bench Power Supply Question.
« Reply #2 on: October 10, 2011, 12:03:02 pm »
To get one of the better lower cost supplies with very stable VDC, good response and no frills, I presume you'll want a linear supply.

A used Agilent E3610A on eBay is typically under $200.  This provides all the output protection needed, you can parallel or series multiple such supplies for more V or A, superb support [ IIRC this model has been around for decades] and WYSIWYG on the voltmeter and ammeter.  For other conveniences, look at the various options in that model line.

On lower cost linear supplies like Mastech however, my feeling is first you want good stable V or A, CC, CV and short circuit protection as a minimum.  Overvoltage is definitely a plus, but if the meter provides stable CV or CC, its the minimum in the absence of overvoltage protection.   In old style linear supplies, very little can go wrong unless you bump the dials and change the dialed output.

The Mastechs voltmeter can be off < 10% on mine, but what the PSUs meters actually show you I feel is secondary to stable output, its prudent to monitor the circuits true V or A through a real time voltmeter and ammeter right at the PCBs power jacks.  While having great meters on the PSU is a plus, and accuracy always helps, there is always some drop on the leads which worsens at high current, so thus the need for sensing terminals and extra costs for the PSU, and this is convenience over what is really demanded of a good PSU. 

Me thinks its better to have multiple quality DMM, dedicating 2 of them to monitoring V and A during bench testing than rely on the PSU of the meters, which will be hard pressed to match the accuracy of a good DMM and will always be slightly off proportionate to load.

Best Wishes,

 Saturation
 

Offline MajorEE

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Re: Forum Intro, and Bench Power Supply Question.
« Reply #3 on: October 13, 2011, 02:23:36 am »
I went ahead and ordered the 9110, Got a good deal on it and will review it for you guys when I get it!

Thanks for the help! I appreciate it! :) ETA 1 week!
 


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