Looking for in expensive linear variable split channel PSU? - Page 1
Forum section: electronics / testgear

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 16, 2015, 06:56:15 pm
content: So ive been looking around for a DC power supply that has a positive and negative channel. The only ones I can find are way out of my budget! Im trying to stay under 200 buck... Im looking for something that can handle at least 24v+/- on each channel I would think one amp of current is sufficient but the more power it can handle the better....I could always build one from a rail spliter, some transistors/fets, and opamps... but really im looking for something in a nice case that just works...Can any one recommend something like this or is an 800 dollar Rigol the cheapest im going to find? Ive been googling and looking on ebay for split supply power supply but have not come up with much. The problem is I want something digital and nice and I dont want to write any code for it... i have better things to do so... buying a cheap one is fine.

author: wd5gnr
author_rank: Regular Contributor
timestamp: June 16, 2015, 08:05:22 pm
content: This only goes +/-15 but I've had good luck with it:http://www.elenco.com/product/productdetails/power_supply=ODU=/same_as_xp720_in_kit_form=NTc4Would be better with meters, and I've often though of adding them, but just another project I never get to.This is in your budget:http://www.circuitspecialists.com/bench-power-supply-csi3003x3.htmlI have no connection to the links, btw.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 17, 2015, 12:35:52 am
content: Hmmm the Elenco looks good for the price, I wish it had at least an 18v output though, may be able to live with a +/-15 though..The second one is more along the lines of what I was looking for but I dont see anything about negative voltages? Do you just use the third output as a virtual ground or something? Also I dont see that it is adjustable??EDIT:Just saw it has 2 variable channels and one fixed, but still no negative? So you just center tap it like two nine volts or something? I was looking for something that would dial in the precise voltage and then split it. for example maybe you connect a pot to a rail splitter that adjust the voltage to whatever you want and gives a precise +/- output that matches and then boosts the current with some transistors or something like that.

author: Vgkid
author_rank: Super Contributor
timestamp: June 17, 2015, 12:39:23 am
content: What country are you located in, and is used ok?

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 17, 2015, 12:40:51 am
content: Im in the US, California used may be ok depending on price and supply.

author: RJFreeman
author_rank: Regular Contributor
timestamp: June 17, 2015, 01:55:59 am
content: Quote from: rwgast_lowlevellogicdesin on June 17, 2015, 12:35:52 amYou press the series Switch and this connects the positive rail of the left hand supply/channel 1 to the negative rail of the one on the right.Since this supply does not seem to have a tracking option, you then adjust the two channels accordingly (so for +/-15V you adjust each rail to 15V)Try a search on Ebay for 'Tracking power supply' there seem to be a few Leader LPS-152 power supplies which do up to +/-25V at 1 Amp at around the $100 USD mark (plus shipping) which should comfortably fit your budget I would expect.Also a Topward TPS4000D for $88 (which if it is the Digital display version of the TPS4000 should give you up to +/- 30V at 2 Amps)A Tracking power supply, is one where you get two rails (as you want) but just have to adjust one side and the other side 'tracks' the side you set

author: macboy
author_rank: Super Contributor
timestamp: June 17, 2015, 12:32:02 pm
content: Quote from: rwgast_lowlevellogicdesin on June 17, 2015, 12:35:52 amWith very few exceptions, dual power supplies contain two independent, floating supplies. This means that you can connect the positive output of one to the negative of the other and use the two together as a +/- supply. Some offer controls to automatically make this connection for your internally and to tie the voltage controls together so that you only need to adjust one. Nonetheless, they all can do what you want if you make the connection and set the two voltages yourself.

author: macboy
author_rank: Super Contributor
timestamp: June 17, 2015, 12:55:05 pm
content: Examples of something that would work for you is- HP/Agilent E3620A (dual 25 V, 1 A, premium quality). used only; very expensive new.- Mastech HY3003 or HY3005 (30 V, 3 or 5 A respectively) - these come in single, dual as well as a triple which adds a 5 V supply. There are alsomanycloned/OEM'd versions of these. Just google images for HY-3003 and you will see. Also a.k.a. GPC-3030D and IPS-2303D (I have the latter).You can also buy two single supplies and tie + of one to - of the other.Consider the built-in meters. Some require you to switch between V and A, or between the two supplies. Some have inadequate resolution. The E3620A needs to switch between the two supplies but the resolution is OK (10 mV and 1 mA). The Mastech meter is inadequate for anything but rough setting (0.1 V resolution), but that's one hidden cost of a cheap supply.I assume that you are using this to power some analog circuits like op-amps? For that I would avoid switching/SMPS supplies and go for a good old heavy linear one.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 17, 2015, 01:44:39 pm
content: Ya Im not sure why I didnt realize just tying the two channels in series would, just like tapping between batteries. I had a more complicated circuit in my head than this needs to be, but yes resolution is very important. I found Agilent E3620A for 200 used..What about two of these?http://www.ebay.com/itm/30V-5A-Precision-Variable-Adjustable-Digital-DC-Power-Supply-Regulated-Lab-Grade-/380937875451?pt=LH_DefaultDomain_0&hash=item58b1aaaffbit claims 3 milli volt accuracy, or .03v. Are these things kind of junky? There super cheap!And yes I want linear no switching this is for analog operation mostly, split rail opamps with +/-18v rails.

author: commongrounder
author_rank: Frequent Contributor
timestamp: June 17, 2015, 02:38:38 pm
content: Also, there is the Korad KA3005-D(or P, programmable)-3S triple linear supply. This has linkable 30 volt 5 amp supplies and a fixed 5 volt supply. There are several discussions in the forum about the pros and cons of this unit, but I have one and it has done the job with no serious problems. There is also a version (KA3003) with 3 amp outputs instead of 5 amp, if you don't need the extra capacity.

author: RJFreeman
author_rank: Regular Contributor
timestamp: June 18, 2015, 01:44:00 am
content: Quote from: rwgast_lowlevellogicdesin on June 17, 2015, 01:44:39 pmThe price is compelling, and you certainly could connect two together, but they have been discussed on these forums here:https://www.eevblog.com/forum/reviews/beware-yihua-yh-305d-bench-psu/