Still struggling to find a proper power supply... - Page 1
Forum section: electronics / beginners

author: Mint.
author_rank: Frequent Contributor
timestamp: June 16, 2012, 11:46:56 am
content: So I've been looking for a power supply for a while now. I will start off by saying that I used batteries as power before, but they really didn't do it for me because I kept on having different batteries all over the place and it was really uncomfortable and inconvenient for me. So then the next thing I did was used old chargers, which did the job alright, except for the fact that I had to had lots of different chargers all over the place. Afterwards I built an LM317 power supply, however it really didn't do it for me. Having a little PCB on the bench with wires from and to the power supply and not to mention to the circuit, ahhh! So messy and I didn't like it.I think that perhaps now I want a proper power supply. My needs are not so great for now. I need about 0 - 15 volts and 0 - 1 amps. My budget would be around 300. Now I've been searching a lot recently and I have came across the choice of a programmable power supply and a non-programmable. I think I need non-programmable as my circuits aren't really that complex and I don't want the extra cost. The next thing is I am not sure which brand and where to buy. I was thinking maybe I could get a nice Agilent and it would last me a while. The Agilent U8001Ahttp://www.home.agilent.com/agilent/product.jspx?nid=-35489.783963.00&cc=AU&lc=engcaught my attention. However I was thinking whenever maybe I should just buy a 100 cheapie off ebay and just use that, plus the repairs may be a bit easier since I assume the circuit would be simpler. So my choice is either invest in a good power supply now that will last me a while, or save up some money and buy a cheapie. Also maybe I should buy used, though I can't find much used power supplies. Please advise.- Thanks in advance!

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 16, 2012, 12:07:52 pm
content: Buy one of the kit supplies, and make it yourself, I am not sure which one is the best, you will have to look around.I think it's a bit of a rite of passage into electronics. I still use my first one.If you look at Dave's lab, there is an Altronic's power supply sitting on the shelf in his new lab. He must have had it for years and probably still uses it.I am hanging out for Dave (x2) and Amspire to finish their psu projects. I am probably going to get/build all three.My budget doesn't stretch to Agilent, and I haven't seen any broken Agilents lying on the side of the road so I guess, I will keep waiting.

author: Psi
author_rank: Super Contributor
timestamp: June 16, 2012, 12:11:44 pm
content: I'm not saying you should definitely do this, but, sometimes it's good to buy two identical cheaper units rather than on expensive one.Obviously the units should still be acceptable quality but two general spec units can be better than one awesome spec unit.For power supplys having two is very useful. Not only because you sometimes need two power sources but because if one blows up you have a spare and you don't have to stop your project to fix it.Also when you do attempt a fix you have an identical working unit to take measurements from. That can be very handy when looking for faults.Once i've narrowed down the products i like to say 5 brands/models i quite often search for service manuals online before buying.If i have a choice i always pick the one with the service manual available.

author: rr100
author_rank: Frequent Contributor
timestamp: June 16, 2012, 12:26:42 pm
content: If you don't have very special requirements just get one of the 30V 3A cheapie from ebay (linear one, the "long" type with two meters in the front, with adjustable voltage and current). It will cover most of the needs, not much that can go wrong (and it's really easy to fix anyway). It can also help "around the house", temporarily replace this or that power supply that blew up (like for printer or netbook), charge lead-acid batteries, etc.It will last you for as long as you can afford the bench space for it.

author: digsys
author_rank: Unknown
timestamp: June 16, 2012, 12:44:38 pm
content: Seeing you're in OZ, check outhttp://www.radioparts.com.auand search HCS3304 1-60V 0-8A 3 DIGI LED DISPLAY(or all their bench top supplies). I've bought several of these and they are GREAT. I know it seems a lot more thanyou want but, trust me, once you have the power capability, you'll use it !! It's also within budget !! If you get atrade account, I think I pay $180 or less. Plus Radio Parts will look after returns / service, been around a LONG time.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: June 16, 2012, 12:57:45 pm
content: Dunno if you need an Agilent for normal hobby bench needs. An buying a cheap Chinese one can be something you will regret.There are however several choices inbetween these extremes.E.g. Thurlby Thandar Instruments (TTi) offer a wide range of good quality PSUs.Doesn't help you down under, but here's a pretty decent one on discount:https://www.distrelec.de/labornetzger%C3%A4t-ch-de/tti/ex355r-price-burner/919817Over here, a typical suggestion would also to look at stuff fromStatronandELVhas also some nice PSUs.Quote from: digsys on June 16, 2012, 12:44:38 pmThis is a Manson PSU which is one of the better Chinese brands. But honestly I wouldn't recommend a switched mode PSU as first and only bench supply. A Manson PSU would be a good choice if you need a lot of power and don't need very fine or accurate regulation, but for hobby electronics, I'd prefer something were you can set the current limit in the low mA range.

author: LEECH666
author_rank: Frequent Contributor
timestamp: June 16, 2012, 02:29:34 pm
content: Mike reviewed a small footprint Manson supply here. His verdict: Seems okay for general purpose lab work.https://www.eevblog.com/forum/product-reviews-photos-and-discussion/tenma-72-8345-bench-psu-review/Florian

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: June 16, 2012, 03:23:44 pm
content: Yeah, but Mike searched one to take around and therefore preferred a switched mode one. For bench use and low currents, a linear one seems to be a better choice.Besides, it can't set the current limitation without a short circuit on the outputs. Big disadvantage IMHO.

author: digsys
author_rank: Unknown
timestamp: June 16, 2012, 11:46:59 pm
content: QuoteSome applications prefer linear, some prefer higher power capability of S/Mode. The OP now has a choice, we just supply the options.QuoteThe HCS3304 that I suggestedimmediatelygoes into current SET mode when you turn the current pot. Then after a few seconds reverts backto READ mode. There is also a control connector, which I reroute to the front, that has on/off and remote DC controlled V_Set and I_Set. All handy.Voltage pot works similar. Also, if you depress eaither pot, they switch to 10X mode. Very nicely thought out.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: June 17, 2012, 12:14:28 am
content: Quote from: digsys on June 16, 2012, 11:46:59 pmThe OP said he required 15V and 1A. That's not the range were you would usually suggest a switched mode supply without any other reason (e.g. portability). Besides, suggesting a 60V/8A PSU implies that more is better, but the higher power usually comes with the price of less accuracy. For tinkering with electronics, I would prefer if I could measure and limit the current in the low mA range instead of being able to get 8A out of my supply.Quote from: digsys on June 16, 2012, 11:46:59 pmIt's just that my comment was obviously related to the Tenma 72-8345 aka Manson NSP 3630.

author: Mint.
author_rank: Frequent Contributor
timestamp: June 17, 2012, 01:02:48 am
content: Thanks for your suggestions everyone.I guess I'm gonna look around for a decent kit and if I don't find anything I will buy a cheapie (any other links for more supplies would be appreciated)

author: Mint.
author_rank: Frequent Contributor
timestamp: June 17, 2012, 04:25:52 am
content: Alright!After a bit of searching I've made the decision to buy a cheapie power supply off eBay, just for now, since it would be easy to fix if I screw it upI have got two options:http://www.ebay.com.au/itm/Adjustable-Variable-Power-Supply-Switch-Mode-30V-5A-Fan-cooling-240V-OZ-WRT-/270920444719?pt=AU_B_I_Electrical_Test_Equipment&hash=item3f141deb2f#ht_2898wt_1144ORhttp://www.ebay.com.au/itm/ATTEN-Adjustable-Variable-DC-Power-Supply-30V-3A-240V-LED-Display-Free-postage-/261028884134?pt=AU_B_I_Electrical_Test_Equipment&hash=item3cc688aea6#ht_2928wt_1144One is linear and the other is switch mode, which should I get?

author: digsys
author_rank: Unknown
timestamp: June 17, 2012, 04:58:00 am
content: [quote ... since it would be easy to fix if I screw it up One is linear and the other is switch mode, which should I get? If the "easy to fix if I screw it up" is important, definitely get the linear ! It will be a piece of cake to fix, off-line S/Mode isdangerous to work on, and when it fails, it can be spectacular :-) As has been pointed out, Linear has less noise as well.

author: Mint.
author_rank: Frequent Contributor
timestamp: June 17, 2012, 05:56:57 am
content: Quote from: digsys on June 17, 2012, 04:58:00 amExcellent! Thanks for the adviceI just bought the supply and i'll probably do a quick teardown of it when I get it

author: rr100
author_rank: Frequent Contributor
timestamp: June 17, 2012, 06:00:12 am
content: The linear one is the type of power supply I was referring to, not much can go wrong with it (and not that much can be screwed up by the manufacturer) and can be fixed easily.They show the switching one sometimes with binding posts sometimes with "banana holes". Maybe you can clear with the seller beforehand which one you'll get, accordingly with your preferences.Frankly I would expect the linear one to be some tens of dollars cheaper, especially compared with the more capable switching one. As it is I would take the chance on the switching one, especially if you want to move it around at times, the linear one is much heavier and larger and you can't even grab it easily to carry it with one hand (and even if you put it in a normal bag, like a shopping bag you need to be careful with the buttons).Edit: wrote the answer before your reply :-)

author: Mint.
author_rank: Frequent Contributor
timestamp: June 17, 2012, 06:18:22 am
content: Quote from: rr100 on June 17, 2012, 06:00:12 amHey thanks for the advice. I don't really need a portable power supply at the moment and it isn't a problem for me if its heavy. I think I've made the right decision - going against the switch mode one