Similar Bench Power Supplies - Page 1
Forum section: electronics / beginners

author: voodoobearhunter
author_rank: Contributor
timestamp: May 24, 2013, 10:18:58 pm
content: Hi,I am currently getting some basic lab equipment to get working on some projects that I have been thinking about and have a question in regard to bench power supplies.Well, one bench power supply in particular.I was looking at the Velleman PS3005D which is around €124 on the UK store.http://www.velleman.co.uk/contents/en-uk/p558_0-30V_DC_0-ps3005d.htmlI have been looking around at alternatives and have found one on farnell that looks identical but is a Tenma 72-10480 which is only €66.25.http://ie.farnell.com/tenma/72-10480/psu-bench-single-3a-30v/dp/2251946They look identical, except that the Velleman is 5A where as the Tenma is 3A.Can anyone tell me if they are the same/similar power supply rebranded or is there a reason that the Tenma one is half the price?Would the 5A vs 3A command such a difference in price and has anyone had experience with the Tenma supply or similar supplies?Also, would this be a good power supply to start out with? I had roughly allowed for budget of €120-€130 so if anyone can recommend a reliable supply I would be very grateful.In regard to usage, I am mainly looking at PIC based projects with an aim to build a PIC controlled ROV. I would also like to possibly get a supply that has extra umph in the likely case I need it for something that needs more power.Apologies if this has been asked before.Thanks!

author: Matje
author_rank: Regular Contributor
timestamp: May 24, 2013, 10:49:56 pm
content: Quote from: voodoobearhunter on May 24, 2013, 10:18:58 pm3A and 5A are kind of standard power specs, so this is why many power supplies exist with these specs.The two supplies are almost certainly rebranded chinese products, a 3A version is always quite a bit cheaper than the 5A version.I have no experience with the devices above, but from experience with other power supplies sourced from China I would expect (asuming these are linear supplies) the 3A version to be able to supply a bit above 2A and the 5A version maybe 3.5A, continuously that is.Both supplies will do the job if you do not expect too much from them.If you want a really reliable power supply (say, for running it unsupervised for long periods of time, wouldn't recommend doing that with the cheap stuff) you will need to buy a name brand one. The chinese devices often are not constructed as badly as one might suspect, but corners are being cut.

author: voodoobearhunter
author_rank: Contributor
timestamp: May 24, 2013, 11:00:52 pm
content: Thanks for the reply Matje.I had been also looking at some others on ebay that are being sold as a sort of surplus stock, or unwanted stock.Not sure if they are a better brand name but the price seems good compared to their retail price.The two I have been looking at are:http://www.ebay.ie/itm/Thurlby-Thandar-EL155-15V-5A-Lab-bench-Power-Supply-PSU-/281112026555?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item4173951dbb#ht_500wt_1156http://www.ebay.ie/itm/Thurlby-Thandar-EL183-18V-3-3A-Lab-bench-Power-Supply-PSU-/281108853405?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item417364b29d#ht_500wt_1414Would something like this be a better buy?

author: Paul Price
author_rank: Super Contributor
timestamp: May 24, 2013, 11:28:56 pm
content: Ever think to make your own?If you have lotsa bucks, you can just go out and buy one.If you have some old equipment to use for parts, you can make your own for near zero cost.Most low power PICC projects require much less than an 1-amp sp you can just build the 5V regulator with just 1 7805 2 caps, on the breadboard or on a small perboard hand wired.For most projects, discarded wallwarts, such as a PC portable power supply can easily provide 18.5V at 3 to 4.5 amps.Some DSL or Router wallwart power supplies will give you 5V regulated or some others .5 to 2 amps at 12V.A basic 0-3 amp power supply is hardly more than a PC Laptop Power Supply, one or two low cost IC LM317 regulators,a capacitor or two, two resistors, a pot for voltage control and some metal box to attach the LM317's to. If you get a small fan from a piece of equipment, it will allow you to cool the two voltage regulator chips enough to get 3-amps out of them.In the circuit below, if you feed it 18V 3amp power supply from a laptop you have a 1.2 to 15V 3Amp short circuit protected supply.

author: MasterOfNone
author_rank: Regular Contributor
timestamp: May 25, 2013, 11:05:56 am
content: Voodoobearhunter,Apart from the 3A/5A difference the Vellemen is a programmable power supply whilst the Tenma isn’t (i.e. programmable via USB/RS232). That’s also part of the reason for the price difference.Also Dave found a serious fault with the initial batch of these power supplies, and the problem(s) have been fixed.https://www.eevblog.com/forum/blog/eevblog-315-korad-ka3005p-review fail/I’ve not had any experience with these PSU myself, but I was looking at the triple output version of the Tenma but then decided to go for a cheap Hantek triple output supply instead. Wow what a mistake that was, I’m now waiting for Rigol to manufacture/deliver my PSU.

author: voodoobearhunter
author_rank: Contributor
timestamp: May 25, 2013, 11:55:35 am
content: Hey MasterOfNone.Thanks for the reply. Yeah I had seen Daves video on it and things seem to be fixed with it.Would you know anything about the Thurbly Thandar supplies. Am edging towards these ones.Wondering which would be handier. 15v 5A or 18v 3.3a.If I needed the extra power I could always build my own supply from an old pc psu as mentioned.Power supply is to be a birthday gift from my wife.Thanks

author: madires
author_rank: Super Contributor
timestamp: May 25, 2013, 12:26:12 pm
content: Quote from: Paul Price on May 24, 2013, 11:28:56 pmThere are also tons of schematics for linear lab PSUs based on 2N3055 and some OPAMPs with constant voltage and constant current. For more Amps simply use more 2N3055s (and a larger heatsink) :-)QuoteLet's start with a linear PSU first. With increasing knowledge and experience he'll know when to use a switching mode or linear PSU. But for starters a linear PSU is the best choice.

author: MasterOfNone
author_rank: Regular Contributor
timestamp: May 25, 2013, 12:47:33 pm
content: Quote from: voodoobearhunter on May 25, 2013, 11:55:35 amSorry I can’t really comment on the TTI power supplies, we have some at work but they are the programmable ones (and I’ve not really played around with them anyway).Hopefully someone with experience of these supplies will reply.

author: voodoobearhunter
author_rank: Contributor
timestamp: May 25, 2013, 02:44:34 pm
content: (edit) Also, just checking the specs of these supplies, they don't have overvoltage protection... Am guessing that that would be handy.If I was to choose one of the Thurlby-Thandars, what would be more important from a hobbiest point of view?More voltage range or more power?

author: voodoobearhunter
author_rank: Contributor
timestamp: May 25, 2013, 02:58:42 pm
content: Apologies for the double post.Just looking at this one too:http://www.circuitspecialists.eu/power-supplies/bench-power-supplies/fixed-dual-output-bench-power-supply-csi-3005x5Anyone had experience with CSI?

author: Christopher
author_rank: Frequent Contributor
timestamp: May 25, 2013, 03:01:15 pm
content: Most of the time you won't need more than 20V @ 2A. I thought I'd need crazy power, but as Dave says you can get to the moon and back on a Milliamp!Go for the farnell one: VERY quick delivery, returns are easy and Tenma are just rebadges. 3A is pleanty.

author: voodoobearhunter
author_rank: Contributor
timestamp: May 25, 2013, 04:37:21 pm
content: Thanks for all the input and comments.I really like the look of the Thurlby Thandar power supplies so I think I will go with one of them.They seem like a really good price compared to their retail price.I am still stuck at whether to go with 15V 5A or the 18V 3.3A.I am thinking the 18V one as I probably won't need too much power.

author: voodoobearhunter
author_rank: Contributor
timestamp: June 04, 2013, 08:14:44 am
content: Just thought I'd do a quick reply now that I have received my power supply.I went for the TTI EL183 18V 3.3A supply.I have it hooked up on my bench and have only used it lightly to power some PIC microcontrollers at the moment as I haven't had much time but it is exactly what I was looking for. It is great to be able to dial in the voltage and current and dead handy for messing with my PICs.The unit looks good too with a slight medical equipment look about it. Seems to be very well built too.There is a guy on Ebay selling the brand new power supplies that are old surplus stock for less than 50% off the last listed price.I found it quite reasonable and the supplies come straight from TTI.Hopefully I'll have many years of tinkering with it.Cheers for all the help.

author: mcoms
author_rank: Newbie
timestamp: September 29, 2014, 05:03:10 pm
content: Although this is an old thread, it came up when I was searching for info on the Tenma 72-10480 PSU.I've done alayman's review on YouTubewhich might help others considering this supply... tl;dr it's got a terrible UI, but for £50 it more or less does what it says on the tin.Can't tell if it's the same one internallythat Dave reviewed— same box, but different features and limits. Hopefully not the same faults!