workbench power supply - Page 1
Forum section: electronics / projects

author: odell
author_rank: Contributor
timestamp: March 14, 2012, 07:51:32 pm
content: I'm looking to get a workbench power supply. but I looking for a workbench power supply in a kit form. So I can put it together myself. What is the best one. I'm looking it to have a lcd.

author: kripton2035
author_rank: Super Contributor
timestamp: March 14, 2012, 08:40:12 pm
content: this one is nice and cheap...http://shop.tuxgraphics.org/electronic/detail_microcontroller_powersupply.html

author: Bored@Work
author_rank: Super Contributor
timestamp: March 14, 2012, 09:27:28 pm
content: Quote from: kripton2035 on March 14, 2012, 08:40:12 pmNot againCheap yes, nice no. The digital control loop is to slow for a reasonable lab bench power supply.

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: March 15, 2012, 01:03:26 am
content: what about the Elenco XP720 Kit form.http://www.elenco.com/product/productdetails/power_supply=ODU=/same_as_xp720_in_kit_form=NTc4

author: Unknown
author_rank: Unknown
timestamp: March 15, 2012, 06:12:19 am
content: Quote from: BoredAtWork on March 14, 2012, 09:27:28 pmI am glad I am not the only one that thinks that. I built one, and thought I had stuffed something up as it was so slow to adjust. It is now consigned to the "failed" box until I learn enough to change it and make it faster.

author: kripton2035
author_rank: Super Contributor
timestamp: March 15, 2012, 07:49:20 am
content: ok not the tuxgraphic...so what about the elv ?http://www.elv.de/output/controller.aspx?cid=74&detail=10&detail2=21996&flv=&bereich=&marke="kompletbausatz" = as a kit...

author: firewalker
author_rank: Super Contributor
timestamp: March 15, 2012, 12:04:32 pm
content: Have a look at this one.http://www.microsyl.com/index.php/2010/03/31/bench-power-supply-0-25v-0-5amp/Alexander.

author: Unknown
author_rank: Unknown
timestamp: March 15, 2012, 06:17:28 pm
content: The ELV one is nice, it's a standard op-amp based supply with floating supplies for the op-amps. Digital control is with PWM signals to set the voltage/current limits I believe. Downside is that international shipping may be expensive. The topic starter has conveniently omitted their location, which means it's probably US.Quote from: firewalker on March 15, 2012, 12:04:32 pmI'm not really impressed by this schematic. Why would someone use a trarlington for the base current, it can't be that high at 5A?

author: kripton2035
author_rank: Super Contributor
timestamp: March 15, 2012, 10:21:18 pm
content: the topic starter also didnt gave us the required voltage and amps he wants ...

author: MikeK
author_rank: Super Contributor
timestamp: March 16, 2012, 11:44:19 pm
content: Quote from: BloodyCactus on March 15, 2012, 01:03:26 amI have one of these. It's okay, but it doesn't have a display. You'd have to add one, which could be considered fun, or a pain.

author: kodai
author_rank: Contributor
timestamp: March 17, 2012, 03:56:59 pm
content: Hey guys, I've been lurking on the forums here the past couple of years but this is my first post. Caught this topic and decided to chime in. I built the Elenco 720 last month and can say its a lot of fun, but comes with a lot of limitations. On the down side, there are a number of resellers out there who have different versions. The most recent is the 2011 revision. Elenco decided that since the binding posts were hard nickel plated and it was difficult to get solder to stick as well as working in cramped quarters (due to their locations), to toss in some extra nuts so you could just "tie" the wires on to the plugs. The included carbon contact pots are some of the stiffest I've ever used. And the caps are no name 20% lytics that hit the very edge of the 20% range.So like many others that have built this kit, I decided that I would do the common upgrades to the caps when I was ordering some stuff from mouser for other projects. Nice new high temp, low ESR panasonic's across the board. Went ahead and spent the cash for some 2k, 10 turn, wire wound pots with new knobs. Used 22 gauge ring terminals on the posts and that worked well to skip buying new posts (wow binding posts have really gone up in price the past few years).Also, the two pieces of heats shrink they toss in are garbage, and there is no heat shrink for the TO packs, so make sure to have an assortment on hand. And the PCB has the largest pads I've seen since I was a kid playing around with 60's era tech. I mean really, really huge and they of course need to be tinned before you start populating the board.Having listed the cons, I can say that it has a lot of pros going for it and its well worth it in the $40-$60 range that most places are selling for. The transformer is of good quality, with silicone covered taps, and the rest of the parts are of very good quality. It should last for several decades if take care of. Its a fun little project that can be moded easy enough. There is plenty of room for a display in the upper left quadrant where the Elenco logo is. I'll add that bit of kit down the road. I like to work on antique radios and the 6.3/12.6 AC rail is nice for old tubes, so its a nice bonus for the price of the unit.On the whole, I would suggest the OP buy a ready to go PSU that meets his needs. But consider building and modding the 720k as a fun, secondary PSU. The 720k is quickly becoming my goto PSU for microcontroller projects and I really like it.

author: odell
author_rank: Contributor
timestamp: March 17, 2012, 09:53:20 pm
content: I found a website today showing how to putt a lcd in a Elenco XP-720 Bench Power Supplyhttp://www.n5ese.com/xp720.htm

author: Unknown
author_rank: Unknown
timestamp: March 18, 2012, 05:22:44 am
content: I have built a couple of high current supplies I use for HAM gear. Nothing special or difficult about them. But after buying a couple of "cheap" micro-controlled supplies of dubious quality and specs. I decided I wanted at least one supply I could trust, so went and bought an Agilent, not programmable, don't need it. Though it can store 2-3 voltages. No scratchy noisy pots or suspect encoders. Now at least I can try and build my own and have something to compare it to.I would suggest doing what I should have done at the start. Which is buy a good "brand" name supply. Then as a learning exercise design and build my own. Unlikely ever to get close to a good brand name but should be at least as good as the no name cheapies, and at least I will know how well it has been put together, or not.

author: DonRon
author_rank: Regular Contributor
timestamp: March 21, 2012, 07:34:41 am
content: Quote from: no_standing on March 18, 2012, 05:22:44 amHi no_standing,Which one did you buy ... one of the U8000-Series?CheersRonald

author: Unknown
author_rank: Unknown
timestamp: March 21, 2012, 10:39:57 am
content: @DonRonYeah, just an U8001. 0-30V 3A single output.I admit I was kind of curious as to what you get compared to the "cheaper" supplies that most of us hobbyists would buy. And compared to what an actual professional lab would use, the U8001 probably is a cheapy. Still the build quality is better, than the other chinese ones I bought, it just"feels" better quality. It was much bigger than I thought and heavier. Only annoying thing is why the bloody hell does the fan need to run flat out from power on. Is it that hard to have thermal control Agilent!. If not for the warranty I'd open it up and "fix" the fan. but first I'll see if it can be changed in the manual, maybe I should read it.Was it worth the $400 aussie I paid for it?. Hmmm, time will tell. If it still works and is in spec in 5 years, I guess so.One positive thing about the chinese cheapies though, I don't fret so much pulling them apart and hacking them.Rob

author: T4P
author_rank: Super Contributor
timestamp: March 21, 2012, 03:44:21 pm
content: Who would have thought at 400 Oz dollars Agilent would at least have thermal cutoff , no !The fan runs at full tilt ... *fail*Some people don't like not having thermal cutoff and some people don't mind ...Well i guess i totally don't mind .After all , don't really like my lab in total silence .

author: saturation
author_rank: Super Contributor
timestamp: March 21, 2012, 07:48:45 pm
content: That's a great general purpose PSU, I'd get one too as soon as I find an affordable used one. However, for the cheapo Chinese supplies, folks should beware that many look a likes don't work a like.It may not be too awful, it depends on what you do with your PSU, but why pay for lesser specs when for the same money or just slightly more, you can get a good one that meets Agilent's criteria for a PSU?http://cp.literature.agilent.com/litweb/pdf/5952-4190.pdfhttps://www.eevblog.com/forum/product-reviews-photos-and-discussion/beware-yihua-yh-305d-bench-psu/msg99162/#msg99162In the above eevblog thread, the Yihua step response is slower and passes considerable ripple voltage. It may just be a bad output capacitor on the model the reviewer received or maybe worse, but without performance testing your gear when you receive it, you'd not notice it immediately. What to test for is listed in the Agilent paper. The turn-on response that Dave does is the simplest core test to do on a PSU, as the youtube user did too. For the other tests, you'd need more gear but most could be available at your lab.Quote from: no_standing on March 21, 2012, 10:39:57 am

author: T4P
author_rank: Super Contributor
timestamp: March 22, 2012, 02:53:32 am
content: I know they might not be better but paying 400$ over 90$ is a big difference .

author: DavidDLC
author_rank: Frequent Contributor
timestamp: March 22, 2012, 04:03:11 am
content: Quote from: no_standing on March 21, 2012, 10:39:57 amThose series 800 are really really heavy, for $400.00 USD I just bought a couple of E3615s.David.

author: nukie
author_rank: Frequent Contributor
timestamp: March 22, 2012, 04:20:17 am
content: E3615A is a marvel of engineering. Unlike the popular E3610A the E3615A has a bigass worldwide 100v/115v/230v switchable transformer. It's pretty robust and hard to kill.Well if you manage to kill it, Agilent has a service manual plus all the schematics you need for repairhttp://www.home.agilent.com/agilent/product.jspx?pn=e3615aU800x series has higher ripple and noise than E36xx series.Finally, if you get one of the E36xx series power supply before 31 July 2012 you get aFREE U1272A 4.5 Digit Multimeter( USA & Canada only) boooooo for worldwidehttp://www.home.agilent.com/agilent/editorial.jspx?ckey=2133877&id=2133877&nid=-35718.0.00&lc=eng&cc=US#

author: saturation
author_rank: Super Contributor
timestamp: March 25, 2012, 01:42:20 pm
content: Thanks, you are right, but the list price is ~2x that of the U800x series. However, its been around long enough I can wait for eBay deals. The deal killer for me is the schematics compared to the U800x. Thanks for pointing that out, didn't bother to check the online manuals, now I have.Quote from: nukie on March 22, 2012, 04:20:17 am