Sh#t power supplies... - Page 1
Forum section: electronics / testgear

author: UnknownVertigo
author_rank: Contributor
timestamp: February 12, 2014, 11:19:02 pm
content: Excuse the french reference but I've had it with trying to find a truly *good* supply. IMHO the hobbyist shouldn't have to drop multiple thousands of dollars to get a well built, versatile and reliable precision supply.As may be apparent by my post count; i'm new here. I've greatly benefitted from all the shared wisdom, Dave's got an awesome community built up here!. I found the blog because I was shopping for a supply. A Siglent caught my eye and so I did some searches and up pops the episode showing rust...OMG! I don't wanna to wonder what crap is inside if I'm spending good money. I want to rest assured there is quality inside....Scratch Siglent.I thought I'd just short circuit the whole process and go straight for brand name...I've got $1,200-1500 to spend on this thing so I checked out Keithley. Well, I'll be darned if there isn't talk about rebranding crap from other manufacturers...which would be fine if the end result all checked out. However, it appears as if the $1,200 price tag really isn't warranted for what I would get: subpar display, "wobbly" dials and menu driven functions that should have dedicated keys....Scratch Keithley.I don't know what to think about Rigol. They seem to be a love or hate kind of company. I've read some really bad stuff and some really good stuff. They show up a lot in the forum, perhaps because they are so widely owned and just cannot help but keep their one-off kinda issues out of the limelight...Considering I don't yet have a strong opinion it's hard to pull the trigger there. I just don't know about these guys.Having one unit with 3-4 outputs would be nice to save on bench space...I have a smallish area to work with. This is a challenge as there are many posts about the drawbacks to having an "all-in-one" kind of supply....so I guess scratch this idea.So now I'm thinking I should just bite the bullet and make room for a few single output units and let them work together to accomplish whatever projects might demand. This means that the $1,200-1500 needs to be divided by 2 or 3...and what would that buy me? Even less quality in a sub $1,000 unit...?There's a ton of data out there...reviews, tear downs, general forum commentary etc...weeding through it all is driving me to drink. Not a good thing to mix with electricity!Can I get some folks ringing in on the topic?Who really makes a quality unit - irregardless of cost (perhaps this is the only way to get quality)?If I can't have quality, well, what's the next best quality/value tradeoff?Which single output unit is best to select with the intent of having it play nice with another or multiple other supplies?I love the TFT-LCD readability on the Siglent supply...anyone else putting that technology to work?Thanks for listening to the rant and thanks in advance for the guidance! Cheers!

author: CM800
author_rank: Frequent Contributor
timestamp: February 12, 2014, 11:22:57 pm
content: I would say getting a used Aglent powersupply from KJDS is a good idea, he has loads of them, very good price (£110 or somthing like that) at 20v @ 5A very precise.. you really can't get much better on that style, i have two myself.

author: free_electron
author_rank: Super Contributor
timestamp: February 12, 2014, 11:35:12 pm
content: lcd, tft touchscreen is all secondary spit-n-polish. if the analog section is crap the entire design is crap.spend your money on a few used E3610A supplies. you can find these for 100..150$. with your budget you can easily buy 3 and you will be set for life.

author: Rigby
author_rank: Super Contributor
timestamp: February 12, 2014, 11:51:42 pm
content: Quote from: free_electron on February 12, 2014, 11:35:12 pmYup. Used HP or Agilent on eBay will go a loooong way for only a little money.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: February 12, 2014, 11:52:23 pm
content: With power supplies all of the value is on the used market.Power Designs makes some great stuff (their precision line is bested only by the HP Precision line).Harison Labs/HP/Agilent/Keysight make some great supplies as well. The 6614A and 6115A(part of the precision line) is an incredible power supply which can be used solo, in series, in parallel, etc. Other Agilent supplies are very solid.Quite simple all of the LCD displays, multicolor interfaces, touch interfaces, etc. are fluff. If you want a real power supply and don't want to pay out the ass, go for something used. If you need calibration, then get that. You can easily get 4 or more supplies for your price point.

author: uoficowboy
author_rank: Regular Contributor
timestamp: February 13, 2014, 12:14:28 am
content: Quote from: free_electron on February 12, 2014, 11:35:12 pmI got three E3610As off of Ebay for $180 shipped. As in, $60 each. They are great power supplies, especially for the money.Some of the older HP/PD supplies are nice too, but if you want a digital display these are probably the best value you will find.

author: free_electron
author_rank: Super Contributor
timestamp: February 13, 2014, 12:40:40 am
content: there you go.and those are rock solid , the service manuals are available and they are easy to repair.

author: senso
author_rank: Frequent Contributor
timestamp: February 13, 2014, 12:57:41 am
content: You only get those prices if you are in the USA.If the OP is not in there, think more in the lines of 200€ for the cheapest ones, IF the seller is even willing to ship them

author: echen1024
author_rank: Super Contributor
timestamp: February 13, 2014, 01:30:14 am
content: I bought my E3610A for $110 shipped. I am also now a proud owner of a 6114A which I bought for $60 shipped broken. A 2N4102 shit itself. But these are really nice, solid supplies that are easy to repair. Get a few, and spend the rest of that money on a good oscilloscope. The quality is evident when you take it apart.

author: nowlan
author_rank: Frequent Contributor
timestamp: February 13, 2014, 02:00:34 am
content: Without knowing where OP is from, still some concern about 120/220 input voltage.I think dave did a tear down on an agilent box which had no transformer taps for 220v.I know the power designs all say 110v on the back.I cant understand why its so hard to find a reputable power supply for hobby use.I managed during my micro controller course using a simple plug pack.Before that had a battery eliminator. Probably a LM317 with resistor selectors inside.

author: VK5RC
author_rank: Unknown
timestamp: February 13, 2014, 02:18:44 am
content: As a bit of an HP nut, I have not found any their gear made after ~1970 that is not multi voltage, recently bought 3644 for approx 250 AUD posted, regards

author: bingo600
author_rank: Super Contributor
timestamp: February 13, 2014, 08:17:02 am
content: I have a E3610 but also 2xTTi PL 154 , and a PL310I regard the TTi's as being as good as the HP's.But easier to get in EU land. They dont stack as well though.Edit: I also have 2 x HP 6632B , if you can afford Them (kj ds) Then they are the best , but they aren't fanless as the above , and have some fannoise.I had to get the fanless ones , to do 24x7 testing. (wifes order)/Bingo

author: Frost
author_rank: Regular Contributor
timestamp: February 13, 2014, 10:27:13 am
content: Quote from: Rigby on February 12, 2014, 11:51:42 pmHere in the EU the available assortment on ebay oftenranges from next to nothing.If you try to buy from the US the older PSUsare typically designed for 110V and offered with eitherno overseas shipping or extremely high shipping costs.

author: mrflibble
author_rank: Super Contributor
timestamp: February 13, 2014, 11:49:54 am
content: Quote from: uoficowboy on February 13, 2014, 12:14:28 amQuote from: echen1024 on February 13, 2014, 01:30:14 amI now officially hate your gringo guts! You lucky bastard americans and your military subsidized heaps of surplus goodies.Try finding the same in Europe on ebay ... no chance.

author: nukie
author_rank: Frequent Contributor
timestamp: February 13, 2014, 12:15:17 pm
content: The E3610a dates back to at least early 1990, and they still work flawlessly. Its a great example of a simple analog design that withstand time. It might not have fancy memory(which is a pain when you have multiturn pot) function but it has no Flash or Nand to deteriorate. No backup battery or firmware to go wrong.A few minor modifications was done and notes in the service manual, try that with a Chinese company... a recent example Korad psu tested by Dave, require some public media pressure for them to realise they have a flaw and prompted some redesign. That's considered a good company, other bottom chain 'company' look at this as a lost of profit. They change company names once a while or spin off a new brand.

author: robrenz
author_rank: Super Contributor
timestamp: February 13, 2014, 12:42:53 pm
content: A fun exercise it to print out the specs of the 6114A/6115A and search for the same specs of Accuracy, line/load reg., stability PARD, ripple, etc in a modern supply. You will need very deep pockets to even get close especially on ripple.

author: mrflibble
author_rank: Super Contributor
timestamp: February 13, 2014, 12:48:02 pm
content: Do I even dare to ask what the ripple spec is?

author: Frost
author_rank: Regular Contributor
timestamp: February 13, 2014, 01:04:17 pm
content: 0,04mV rms / 0,2mV peak to peak

author: robrenz
author_rank: Super Contributor
timestamp: February 13, 2014, 01:17:09 pm
content: 6114A/6115A manual/specshere

author: bingo600
author_rank: Super Contributor
timestamp: February 13, 2014, 01:40:48 pm
content: Quote from: mrflibble on February 13, 2014, 11:49:54 amMy 3610 was 75 euro , but needed 2 caps exchanged , and a double ipa washdown (elco goo)/Bingo

author: Rigby
author_rank: Super Contributor
timestamp: February 13, 2014, 02:28:22 pm
content: http://www.ebay.com/itm/HP-6114A-Precision-Power-Supply-020V-2A-2040V-1A-65335399-/310873020499$10.4 days left, and the price is likely to go up now that I've posted it here, but this is a good supply and it's known-working at least to some degree. Great supply.

author: Jasper
author_rank: Contributor
timestamp: February 13, 2014, 02:46:37 pm
content: Quote from: Rigby on February 13, 2014, 02:28:22 pm'ships to united states' only is pretty useless, though.Quote from: VK5RC on February 13, 2014, 02:18:44 amThat E3610 in echen's video doesn't seem to be 230 capable, and it certainly isn't pre-75.

author: eurofox
author_rank: Unknown
timestamp: February 13, 2014, 02:52:18 pm
content: People in EU don't be desperate here you can buy those power supply'shttp://www.woutersenwouters.be/products/power-supplies

author: echen1024
author_rank: Super Contributor
timestamp: February 13, 2014, 02:52:27 pm
content: Quote from: Rigby on February 13, 2014, 02:28:22 pmYou worthless piece of shit. Sorry if that's harsh, but I was intently watching that supply hoping to snag it for a good deal. Well, I have one already, better let this one find a good home.

author: mrflibble
author_rank: Super Contributor
timestamp: February 13, 2014, 03:01:08 pm
content: Quote from: eurofox on February 13, 2014, 02:52:18 pmAt those prices? Let the desperation continue!

author: bingo600
author_rank: Super Contributor
timestamp: February 13, 2014, 03:02:02 pm
content: Quote from: echen1024 on February 13, 2014, 02:52:27 pmThat was not a needed comment/Bingo

author: bingo600
author_rank: Super Contributor
timestamp: February 13, 2014, 03:04:53 pm
content: Quote from: mrflibble on February 13, 2014, 03:01:08 pmAgreed almost new prices/Bingo

author: robrenz
author_rank: Super Contributor
timestamp: February 13, 2014, 03:22:07 pm
content: Quote from: echen1024 on February 13, 2014, 02:52:27 pmDon't you realize that everyone that is interested has email notification set up for these things? Thinking no one but you realized this thing existed until Rigby posted it is naïve.

author: mrflibble
author_rank: Super Contributor
timestamp: February 13, 2014, 03:26:56 pm
content: Quote from: robrenz on February 13, 2014, 03:22:07 pmI should hope he realized that... But it has to be said that goodies that are plastered all over a forum generally don't go for the low low prices you can sometimes get with a lucky snipe.

author: Rigby
author_rank: Super Contributor
timestamp: February 13, 2014, 03:32:04 pm
content: Quote from: echen1024 on February 13, 2014, 02:52:27 pmDamn, dude. A simple "I was hoping to snipe that, now everyone knows," would have sufficed. Edit: by the way, not everyone will react as calmly to this as I have. Beware your reactions in the future if you wish to gain respect from anyone. You lost a lot of respect from me with that comment. My own mother has called me worse, so my skin is a bit thicker, but I don't talk to her anymore because of things like this. Don't be surprised if continued behavior like this results in less assistance in this forum laterQuote from: robrenz on February 13, 2014, 03:22:07 pmYep. Carefully crafted searches set to email you are the very best way to find these things. Now, just like the power supply, anyone reading that didn't know about this now does.

author: nanofrog
author_rank: Super Contributor
timestamp: February 13, 2014, 03:48:55 pm
content: Quote from: echen1024 on February 13, 2014, 02:52:27 pmYou're not the only one interested, I'm sure.

author: TMM
author_rank: Frequent Contributor
timestamp: February 13, 2014, 04:59:37 pm
content: The whole colour LCD wannabe voltage reference precision thing is a wank. Not much point having 1mV resolution when most of the time your leads are going to be dropping orders of magnitude more than that.I use a $300 chinese built linear supply with analog knobs and 7-seg displays (0.1V resolution). If i need a precise voltage out comes the multimeter... and it's measured at the end of the leads. The only feature that would have me spend over $1k on a powersupply is LXI/ethernet and even then i probably wouldn't end up using it as my main supply because it'll probably have a wanky non user friendly interface.My 2c.

author: Rigby
author_rank: Super Contributor
timestamp: February 13, 2014, 05:44:29 pm
content: Quote from: TMM on February 13, 2014, 04:59:37 pmOne thing that I really dig about my Power Designs 3650-S is that it has sense wires, and can do Kelvin 4-wire measurement of the actual power being delivered. I guess that's what makes it a precision supply over a regular supply.Like you, though, I don't have any need for this precision at all. I'm sure there are applications which require perfect power, but I'm not working on those. The analog meters on my supplies all provide enough precision for the hobby work I'm doing.It is TOO EASY to get into the hobby of upgrading test gear, isn't it?

author: robrenz
author_rank: Super Contributor
timestamp: February 13, 2014, 06:28:17 pm
content: Quote from: Rigby on February 13, 2014, 05:44:29 pmI have no idea what you are talking about

author: HiTech
author_rank: Regular Contributor
timestamp: February 13, 2014, 08:42:20 pm
content: Don't mess around with other brands- just go for HP Power Design, Trigon, Sorensen. They all have models with dual/triple outputs are are bulletproof. Yes they will be used and the better deals are online auctions but they are plentiful and shop wisely.

author: Sbampato12
author_rank: Regular Contributor
timestamp: February 14, 2014, 01:19:05 am
content: I had got 2 E3649 from hp/agilent/key...They are to me like a canon shot to kill a fly, but you know. When I visited the website, and saw they were for sale for just US$300,00, new units, with 5 years warranty, and 3 years calibrated, I couldn't resist. I just bought the 2 they had on stock. I think I did a good purchaseI can't find nothing wrong with them. Very precise, ease to use. And it got the programable functions, but only by GPIB...

author: TMM
author_rank: Frequent Contributor
timestamp: February 14, 2014, 03:25:12 am
content: Quote from: Rigby on February 13, 2014, 05:44:29 pmEven with sense wires there is only so far you can go because of the inductance in the leads. Best off just re-regulating locally on the device if it needs to be precise imo

author: Rigby
author_rank: Super Contributor
timestamp: February 14, 2014, 03:54:06 am
content: Quote from: TMM on February 14, 2014, 03:25:12 amI'm not sure how much I need to worry about sense lead inductance on a DC supply.The manual does recommend a shielded twisted pair for the sense wires, though, so what do I know?

author: TMM
author_rank: Frequent Contributor
timestamp: February 14, 2014, 06:24:42 am
content: The sense feedback will compensate for the lead resistance but in practice will never fully compensate for the inductance so transient performance will still suffer.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 14, 2014, 04:06:52 pm
content: UnknownVertigo, I don't know what country you live in. I have the Agilent E3610A and like it very much. Here is a link for 4 units for $440 USD and another $99 for shipping.http://www.ebay.com/itm/Agilent-E3610A-8-15-V-3-2-AMP-Dual-Range-Power-Supply-qty-4-units-/310753946643?pt=LH_DefaultDomain_0&hash=item485a60ec13Four will stack neatly on top of each other and the footprint is pretty good. I wish I had the disposable cash to buy them myself.

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 04:58:02 pm
content: I don't know why you guys are hellbent on old crusty power supplies. For today's hobbyist, they suck.Why you ask? Well, because projects are different than what they used to be 50 years ago. You need AT LEAST mA readings from the supply (and I mean digital display), otherwise you'll end up having to use a separate DMM for that. Same goes for voltage. Why have two extra pieces of gear just so you get something that a decent supply should already provide given today's technology state?As for the cheap agilent ones, they suck in two ways: 1) 10 mA reading resolution and 2) no way to set the current while you're outputting stuff. You have to push that damn button that basically shorts the output to ground. That's... impractical to say the least and if you want 1 mA resolution you'll have to short them yourself, with your DMM (awesome! ... not).Now... aside from mA reading, you need mA (edit: output) resolution! if you can go lower than that, that's even better!Also, the bench supply needs to be programmable and have a way for you to output the readings to the PC so you can analyze and characterize stuff, as you advance (even as a hobbyist) this becomes a need more and more often.That being said, regardless of how simple linear supplies are and how easy it is to make the digital side, there seems to be a shortage of good bench supplies out there, but I wouldn't go as far as recommending super old supplies or old designs that are simply unsuitable for what your usual noob or hobbyist does on his bench today.

author: c4757p
author_rank: Super Contributor
timestamp: February 14, 2014, 05:09:10 pm
content: I have yet to require mA resolution on a power supply, and I suspect this is similar to the people who think they need an 8 digit DMM.mV resolution is nice for finicky digital stuff - Power Designs FTW.

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:10:14 pm
content: Quote from: c4757p on February 14, 2014, 05:09:10 pmYou'll need mA resolution the moment you start designing things that have to run on batteries.Edit: The mA resolution (and lower) for output is useful for testing low power loads, like LEDs.

author: c4757p
author_rank: Super Contributor
timestamp: February 14, 2014, 05:11:46 pm
content: I have a DMM for that. Why do I need do combine them?

author: echen1024
author_rank: Super Contributor
timestamp: February 14, 2014, 05:12:12 pm
content: Quote from: jadew on February 14, 2014, 04:58:02 pmUh huh. And why do I bother with a 70 MHz oscilloscope anyways. Everyone knows that to get good measurements, I needat least10GHz.

author: rdl
author_rank: Super Contributor
timestamp: February 14, 2014, 05:13:19 pm
content: QuoteYou are try to use the power supply as a meter, not what it's for.For that you need a multimeter that reads microamps.

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:15:20 pm
content: Quote from: echen1024 on February 14, 2014, 05:12:12 pmIf you were using it to analyze 10Ghz signals, then yes, otherwise I don't see the point of this comment.

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:16:22 pm
content: Quote from: rdl on February 14, 2014, 05:13:19 pmSo in order to use one of those old supplies I need 2 DMMs attached to it on top of the ones I already need to check the circuit under test?Edit: And yes, it should behave as a meter as well, that's why they are called bench supplies and not wall adapters.Edit 2: Again, today, we can do those readings extra cheap, so why not?

author: echen1024
author_rank: Super Contributor
timestamp: February 14, 2014, 05:17:25 pm
content: Quote from: jadew on February 14, 2014, 05:15:20 pmMy point is, many of us cannot afford the high end power supplies that you are pointing at. We must live within our means, and purchase what we can afford. Therefore, we will buy power supplies like the Agilent E3610A, which is a high quality, Agilent, with a good feature set and it won't break the bank. Sure, your Chinese POS might let you set voltage and current to 1mV/mA, but do you really trust the output?

author: c4757p
author_rank: Super Contributor
timestamp: February 14, 2014, 05:17:40 pm
content: Of course you don't.We think you are being silly and claiming things are necessary when they are far from it. If a noob can't make do with a basic power supply, he has a real problem, and it ain't the gear.There is a difference between "want" and "need", and I'm not sure you understand it.

author: mrflibble
author_rank: Super Contributor
timestamp: February 14, 2014, 05:17:54 pm
content: Quote from: jadew on February 14, 2014, 04:58:02 pmSince you are in Europe, I agree 100% with you. Stupid crusty old power supplies. If I were you I would get a new Chinese one with nice digital readout.That leaves more crusty old psu's on ebay for me.

author: rdl
author_rank: Super Contributor
timestamp: February 14, 2014, 05:20:40 pm
content: Quote from: jadew on February 14, 2014, 05:16:22 pmNo, you need a DMM to read micro amps, that's what they are for. Measuring. The power supplies only have indicators, they are for providing power, not measuring.

author: sync
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:24:30 pm
content: Quote from: jadew on February 14, 2014, 04:58:02 pmYes, that annoyed me. I have mod my E3610A to 1mA resolution. But how accurate are the current reading on the cheap chinese power supplies? Anyway, it doesn't matter when the turn on spike killed the project.QuoteWrong. It doesn't shot the output. That would be silly. The power supply is working normally while pushing the button. It only switches the current meter from reading the actual current to the set current.

author: rollatorwieltje
author_rank: Unknown
timestamp: February 14, 2014, 05:28:26 pm
content: Quote from: jadew on February 14, 2014, 05:10:14 pmBench power supplies are crap for that, most have a huge output capacitor and very slow current regulation. Basically it's only constant current to the output capacitor.Also on my Agilent E3615a pressing the current set button certainly doesn't short the output, it only changes the input to the current meter.

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:29:15 pm
content: Quote from: sync on February 14, 2014, 05:24:30 pmfor 1). It's pretty easy to get really good mA reading and even uA.for 2), if that's the case, I stand corrected, I was under the impression that it shorts the output in order to show the set value.

author: UnknownVertigo
author_rank: Contributor
timestamp: February 14, 2014, 05:31:28 pm
content: Quote from: jadew on February 14, 2014, 04:58:02 pmThanks for all the good conversation folks!There was a question about my location. I'm in the US...should add to my profile.I liked the suggestion of using 2-3 e3610a supplies. My issue is that as a bit if a noob I'm curious about the lack of OV/OC protection...especially if we're talking running in series or parallel. This also begs the question about Dave's point on the supply not having a output on/off. Seems like a supply better suited for the guys who know exactly what they are doing and can avoid damaging their circuit when hooking up multiply units that may not be aware of each other's existence.Any thoughts in the next model up from the e3610a...something like the e3632a or e3642a? More forgiving?To the quote above. Cheap is relative. I've yet to feel like any test equipment is actually cheap. Agilent always seems to be top buck. Can you explain this statement more?Also, you share a lot of information yet haven't commented on what your solution is to the issues mentioned. What do you use?Sent from my iPhone using Tapatalk

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:32:29 pm
content: Quote from: rollatorwieltje on February 14, 2014, 05:28:26 pmYeah, that's definitely one of the decisions one has to make when making a bench PSU, good current regulation or good transient response. Personally I prefer super small output capacitance and have a capacitor (of the right value) in the project I'm powering, if I need it.

author: sync
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:32:40 pm
content: Quote from: jadew on February 14, 2014, 05:29:15 pmOk, which power supply do you recommend?

author: jadew
author_rank: Frequent Contributor
timestamp: February 14, 2014, 05:40:10 pm
content: @ UnknownVertigo and syncI wouldn't know, I'm looking for a new supply as well and I don't know what to chose. I'd go for the Rigol but it's too big for my desk and I'm not sure I want to spend that much anyway.Currently I'm using a home made PSU 0-20V, 0-1A with 5mV/1mA output resolution and 1mV/0.1mA reading resolution.I'm contemplating building another one 0-30, 0-3A but I find it hard to find good enclosures and heatsinks with out paying a lot.The heatsink could be shrinked by simply switching the transformer tap based on the output voltage (ignoring the set one), which is what I think the Korad one is doing and why it has that weird ramp up.Anyway, I don't know what is best or what to suggest, but I strongly feel that old PSUs are not the solution for someone starting up with electronics or for the hobbyist.

author: Frost
author_rank: Regular Contributor
timestamp: February 14, 2014, 05:51:49 pm
content: Quote from: sync on February 14, 2014, 05:32:40 pmAgilent B2962A

author: UnknownVertigo
author_rank: Contributor
timestamp: February 14, 2014, 05:58:19 pm
content: Quote from: Frost on February 14, 2014, 05:51:49 pmhaha, awesome. I'll buy two.seriously though, supply...not source. The difference between those two words is the difference between me sleeping in the bed or on the couch.

author: sync
author_rank: Frequent Contributor
timestamp: February 14, 2014, 06:04:17 pm
content: Quote from: jadew on February 14, 2014, 05:40:10 pmMaybe this?http://www.home.agilent.com/en/pd-1000001614%3Aepsg%3Apro-pn-66311B/mobile-communications-dc-source-15v-3aSmall, programmable and should be capable topreciseaccurate measure down to a few 10uA.

author: Frost
author_rank: Regular Contributor
timestamp: February 14, 2014, 06:14:01 pm
content: Quote from: UnknownVertigo on February 14, 2014, 05:58:19 pmAsk as a person, who can't speak english very well, is there a big difference?In the wikipedia I found: "A power source is an electrical power supply"

author: UnknownVertigo
author_rank: Contributor
timestamp: February 14, 2014, 06:14:17 pm
content: Quote from: sync on February 14, 2014, 06:04:17 pmSpecs look good but no terminals in the front...not the best for my bench.btw, when looking for used units I know that pics can be telling. What should I think when a pic shows a powered on unit with no leads attached but voltage and or current readings of anything but 0?

author: sync
author_rank: Frequent Contributor
timestamp: February 14, 2014, 06:21:11 pm
content: Quote from: UnknownVertigo on February 14, 2014, 06:14:17 pmDepends. When it displays the set current then there is nothing wrong.

author: UnknownVertigo
author_rank: Contributor
timestamp: February 14, 2014, 06:21:20 pm
content: Quote from: Frost on February 14, 2014, 06:14:01 pmYou're right bud and your english is fine. I read source and supply as the same.Agilent seems to change their terminology though...and when calling a product a source it means many thousands of dollars. If they call it a supply then it's more affordable.Sorry for the confusion. Just making light of that fact.Sent from my iPhone using Tapatalk

author: bingo600
author_rank: Super Contributor
timestamp: February 15, 2014, 02:44:10 am
content: Quote from: rdl on February 14, 2014, 05:20:40 pmDid you look at the specs. Of the hp6632b's i mentioned above. Their meter readout is more accurate than most handheld dmms. Mening you dont need to tie up one or more meters to read v/i , just look at the psu meters./BingoSuggestionshttp://www.ebay.com/itm/HP-Agilent-E3630A-DC-Power-Supply-35-W-Triple-Output-6V-2-5A-20V/151229604982http://www.ebay.com/itm/AGILENT-HP-6623A-TRIPLE-OUTPUT-SYSTEM-HP-IB-DC-POWER-SUPPLY-20V-50V-40W-80W/151229648884http://www.ebay.com/itm/HP-Agilent-Model-6632B-0-20VDC-5A-Power-Supply-/171238502056The 66xxoutput on the back isn't that Big a problem to SolveThe 66xxA models have LCD that can be Haarder to read than the VFD on the B'sTooms has some info herehttp://www.tooms.dk/?page=http%3A//www.tooms.dk/Tblog/Showblog1.asp%3FY%3D2012%26M%3D4

author: Rigby
author_rank: Super Contributor
timestamp: February 17, 2014, 10:14:02 pm
content: Quote from: Rigby on February 13, 2014, 02:28:22 pm

author: uoficowboy
author_rank: Regular Contributor
timestamp: February 17, 2014, 10:34:46 pm
content: Quote from: jadew on February 14, 2014, 04:58:02 pmMy Power Designs TW5005W has a switch that toggles the full scale meter reading between 50 and 500ma. I can easily get single ma readings from that.All the features you describe sound great, but are total overkill for 99.99% of what people do. You sound like you're describing an Agilent or Keithley source meter.

author: jadew
author_rank: Frequent Contributor
timestamp: February 18, 2014, 12:54:00 am
content: Quote from: uoficowboy on February 17, 2014, 10:34:46 pmI'm not crazy enough not to admit that in 99% of the cases you don't need that kind of functionality. That applies to me as well, however there's that 1% when you could benefit from such features and the fact that they're so cheap to implement makes me want a PSU that does that.Yes, the cheap Chinese PSUs that have those features are not trustworthy because... well, bad design, not because you can't make a good PSU that cheap.With the HP/Agilent ones you always have to make a compromise: price, chunkiness or specs. That is because they are overpriced (at least in the EU). Obviously good supplies otherwise, but that's a bit beside the point when all you had was $100-200 and the supply you got for that price doesn't do too much to begin with.Finally, yes, I like the crusty supplies as well (heck, I might even get one in the end), but my point is that we're in 2014 and I expect to find a few supplies out there that are well built, have good specs (as the ones I listed) and are affordable. I just couldn't find that supply yet.

author: Rigby
author_rank: Super Contributor
timestamp: February 18, 2014, 02:25:24 am
content: For new supplies, pick any two of the following:Well builtWell spec'dWell pricedThe older the supply, the closer you can get to all three.

author: echen1024
author_rank: Super Contributor
timestamp: February 18, 2014, 02:29:41 am
content: Quote from: Rigby on February 18, 2014, 02:25:24 amExactly. Look at my HP/Agilent/Keysight 6114A for an example. Price: $60 shipped, around $100 for a good condition. Performance: Incredibly good, approaching that of a calibrator. Build: Old HP. Need I say more?

author: uoficowboy
author_rank: Regular Contributor
timestamp: February 18, 2014, 03:40:32 am
content: Quote from: echen1024 on February 18, 2014, 02:29:41 amI will say that the current display of the 6114A is limited... I do wish it had a switch to select between different current ranges. Otherwise a really excellent supply.Plus, if you have one of the newer versions, it doesn't have any sort of power on indication. Who thought that that was a good idea? Seriously...