Symmetric, Double or single PSU? - Page 1
Forum section: electronics / beginners

author: Varal
author_rank: Contributor
timestamp: May 24, 2010, 11:57:19 am
content: Hi thereI want to build a regulated(0-30V 0-5A or maybe 0-3A) PSU for my home lab (preferably using an already existing schematic - I don't have enough knowledge to design my own). But before I start searching for any projects I would like to ask the more advanced users what is their opinion on the question asked in the subjectI don't have many experience myself but I will probably end up doing a few audio amps also often opamps have to be used in a project. This requires symmetrical voltage. Maybe I should just treat audio applications as an individual category and design power supplies individually for those and use negative voltage converters in any other application that would require symmetrical voltages? This would narrow my search to single output or double output PSUs.Also if I were to look for just a positive output PSU, should it have two sets of output terminals or one set would be enough?I'll be grateful for every tip and hint

author: EEVblog
author_rank: Unknown
timestamp: May 24, 2010, 12:45:06 pm
content: One of the most useful supplies I have is this one:http://siliconchip.com.au/cms/A_30603/article.htmlhttp://us1.webpublications.com.au/static/images/articles/i306/30603_8mg.jpgJust simple fixed voltage outputs, plus and minus.Dave.

author: Unknown
author_rank: Unknown
timestamp: May 24, 2010, 01:58:46 pm
content: You'd normally have two output terminals for a single power supply. You could have just a positive terminal and connect the negative terminal to the ground connection in the wall outlet, or connect the negative terminal to a ground pin you hammer into the ground, but just connecting it directly to the lab supply is by far the easiest and best solution. A lab power supply will usually be floating, so neither of the terminals might be at ground potential.A dual power supply is just twice a single power supply, no difference from a design point of view. Many commercial dual lab supplies will have parallel/series mode, with automatic tracking in the latter mode. This is like a symmetrical power supply: if you adjust the positive rail, the negative rail will follow. This is very useful for op-amp circuits, although you can manage with manually adjusting both rails. This is more complex than just a simple power supply, so it might be a good idea to start with a simple single supply.

author: xani
author_rank: Frequent Contributor
timestamp: May 24, 2010, 05:08:15 pm
content: Imo either build two () or build other PSU with +15V/12V and +5V then u can just connect (+) of one to (-) of other and get symmetrical supply ;]Or use computer PSU (u can get them cheap, esp. used) for driving things needing symmetrical output (just remember that they dont have regulated current AND some (5v/3.3v) votages can put several amps on line)

author: Varal
author_rank: Contributor
timestamp: May 24, 2010, 05:15:51 pm
content: Thanks everyone for your tipsDave can you be so kind and tell me how much current can that power supply handle? Do you have an article somewhere about it too? I tried looking for it but the only way to access it seems through the silicon chip website but i can't afford that atm.