buying power supply 3A or 5A? - Page 1
Forum section: electronics / general

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 10:43:44 am
content: Hi,I'm planning to buy a bench power supply...what should I choose: 5A or 3A?I'm doing a lot of logic stuff, but i would try to make some power stuff also...

author: Psi
author_rank: Super Contributor
timestamp: November 03, 2012, 10:47:25 am
content: I have a 3A and it's not enough sometimes.

author: sotos
author_rank: Frequent Contributor
timestamp: November 03, 2012, 11:10:48 am
content: Go for the biggest you can afford.

author: sotos
author_rank: Frequent Contributor
timestamp: November 03, 2012, 11:27:55 am
content: By the way im selling this one here for 260 USD dollars plus 65 USD for secure shipping.AGILENT AGT-U8002A DC Power Supply, 30V, 5AIts new.

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 11:50:43 am
content: Quote from: Psi on November 03, 2012, 10:47:25 amand if it's not enough what you do?

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 11:51:30 am
content: Quote from: sotos on November 03, 2012, 11:27:55 amcan you post some photos?

author: McMonster
author_rank: Frequent Contributor
timestamp: November 03, 2012, 11:57:07 am
content: For how long you're playing with electronics now? What other gear you have? If you're starting, this is your first PSU and you don't immediately have a specific need to have higher current then 3 A PSU is more than enough. When you realize this is not enough yo can always try building your own to whatever specs you want.

author: madires
author_rank: Super Contributor
timestamp: November 03, 2012, 12:06:16 pm
content: Hi sotos!Quote from: sotos on November 03, 2012, 11:27:55 amA while ago you offered a Picotest bench DMM in a thread discussing 5.5/6.5 digits bench multimeters. I sent you a forum message and an email via the forum to tell you that I would like to buy the Picotest DMM, but haven't received any answer. I might be wrong, but it seems there's something fishy. Please correct me if I got that wrong.

author: Unknown
author_rank: Unknown
timestamp: November 03, 2012, 12:25:34 pm
content: I'm playing for 3 years, (discovered electronic at school) and then decided to take as a hobby... Other gears i have: well i have an old oscilloscope (whitout probes, not mine but from my uncle ), a capacitance meter (for not becoming mad whit capacitor) a chinese meter (that i think the battery blown up and destoyed some componets inside it) and a homemade contact printer for PCB and an analog multimeter less than $30 (i use it for making relay circuits and PLC)...Anyway, speaking about the power supply, i can't build my own: i'm not so expert for now and you have the big obstacle of the transformer: where you find or buy it?

author: sotos
author_rank: Frequent Contributor
timestamp: November 03, 2012, 12:33:20 pm
content: Quote from: madires on November 03, 2012, 12:06:16 pmHello friend.Although not the place here to discuss this, but I want to tell that it was bought immediately local here in my city, as I had placed it also in a local electronics forum. The person came here tested it (which was new in the box) and gave me the money.

author: tlu
author_rank: Regular Contributor
timestamp: November 04, 2012, 03:08:16 pm
content: If you build a PSU from an ATX computer power supply, what is the max current output 1A?

author: olsenn
author_rank: Frequent Contributor
timestamp: November 04, 2012, 04:08:19 pm
content: I have the Instek GPS-4303, which has two 0-30V, 3A PSU's, but I can put the two in series to get one 60V supply, or the two in parallell to get one 30V 6A supply. For what I do (mostly powering IC's etc) I never need anywhere near the 3A anyways though.

author: M. András
author_rank: Super Contributor
timestamp: November 04, 2012, 04:19:34 pm
content: Quote from: tlu on November 04, 2012, 03:08:16 pmupto 100 amps or more if you have a high enough watte atx psu

author: Unknown
author_rank: Unknown
timestamp: November 04, 2012, 05:46:23 pm
content: building one form an ATX.... and the regulation? transistors+ cheap analog panel meters? interesting because you don't spend too much and have also a multi voltage /current range....

author: Unknown
author_rank: Unknown
timestamp: November 04, 2012, 05:56:57 pm
content: Quote from: olsenn on November 04, 2012, 04:08:19 pmyes, but for having more out power you need 2 PSU, which actually is REAL expansive....Have you ever done power electronics projects?

author: mariush
author_rank: Super Contributor
timestamp: November 04, 2012, 06:33:00 pm
content: I've bought a Tenma 2x32v 3A + 5v @ 2A fixed linear power supply.Posted pictures here:https://www.eevblog.com/forum/product-reviews-photos-and-discussion/tenma-72-8695-2-x-32v-3a-5v-2a-mini-review-teardown/?topicseenYou can couple the two channels to do 64v 3ain my opinion, up to 64v 3a on a linear psu is great to test even small amps.If you need more current, it's possible to tweak an atx power supply to output up to about 15-18v by tweaking the feedback of the controller, so you'd have 10-15a at hand. Or you could just go for a 24v psu straight away, they're not that expensive.I guess you could always use a pair ofLT1083or something similar to smooth out the ripple and get something close to a linear power supply.

author: tom66
author_rank: Super Contributor
timestamp: November 04, 2012, 11:24:09 pm
content: Or if you need an insane amount of power, use server power supplies.I got two 12V, 98A ones on eBay for £6, including postage. That's nearly 2.4kW in 2U form factor. They do need forced air cooling though... no fans built in.

author: T4P
author_rank: Super Contributor
timestamp: November 05, 2012, 10:01:05 am
content: Quote from: tom66 on November 04, 2012, 11:24:09 pmOf courseThey rely on massively loud fans at the back or built in Air-conditiong that blows in from the bottom, like most server rooms do

author: nctnico
author_rank: Super Contributor
timestamp: November 05, 2012, 11:21:43 am
content: I'm thinking about buying on of these:http://www.ebay.com/itm/261050328132The maximum power is 100W. Up to 20V it can output 5A, at 60V it can output 1.6A. I think there are reviews of this PSU on this website.

author: Unknown
author_rank: Unknown
timestamp: November 05, 2012, 02:28:52 pm
content: Quote from: tom66 on November 04, 2012, 11:24:09 pmI don't need at all an insane amount of power such as 100A...

author: Unknown
author_rank: Unknown
timestamp: November 05, 2012, 02:36:27 pm
content: Quote from: nctnico on November 05, 2012, 11:21:43 amI' don't have time now to search for reiews... I'm pretty busy at the moment, Anyway, it looks great(and cheap also), but actually i don't think to have the need of 60V, 30 should be right...If you find some reviews of this PSU, i'd be glad if you post here