Beginner bench supply - Page 1
Forum section: electronics / beginners

author: Alc
author_rank: Newbie
timestamp: May 18, 2020, 11:55:10 pm
content: Hi all,Looking for my first bench supply. I'm starting to get into home automation, so mainly things like nodemcu/arduino but also LED strips. As a 5m run of SK6812 comes in around 20amps @ 5v, I have been looking at either going for a new one of these -https://www.circuitspecialists.eu/power-supplies/bench-power-supplies/switch-mode-dc-bench-power-supply-adjustable-0-30v-0-20a-csi-3020sw/or a second hand one of these -https://uk.rs-online.com/web/p/bench-power-supplies/4938000/.Obviously, there is a big difference between the new price of these two so I was wondering which would be best for my needs? Or if anyone else has any suggestions that would be greatly appreciated. I'd like to stay below £150 if possible (the 2nd hand 3016-20B is slightly over this admittedly).Many thanksStay safe

author: John B
author_rank: Frequent Contributor
timestamp: May 19, 2020, 12:47:44 am
content: The cheaper one is switchmode, while the more expensive one appears to be linear. 20A is a substantial linear supply and will have a lot of material in things like the transformer, among many other things adding to the cost. For simple stuff like led strips, a switchmode unit will be a far more sensible and cost effective option.

author: wizard69
author_rank: Super Contributor
timestamp: May 19, 2020, 01:59:30 am
content: First off it will not be possible to cover all needs with one supply.Quote from: Alc on May 18, 2020, 11:55:10 pmFor LED strips that you might install permanently, I'd go with UL listed power supplies designed for the strips. This simply to cover your behind for any future insurance claims. Beyond that you don't want a bench supply tied up powering light strips.QuoteFor a first bench supply I wouldn't buy any of those as a first supply. This mainly because a separate supply for your microprocessors is a good thing. At the very least I'd want a supply that has a short range variable supply up to 5 volts and probably a 0 to 30 volt DC supply.QuoteIf you want cheap I'd cobble something together until you can afford a supply or supplies, that covers your initial needs. It is better to buy something with good quality and the features you need. One of those features is at least two channels or two power supplies. An option is to build a fixed voltage supply for your microprocessors and then use a variable voltage supply for your other needs.

author: cdev
author_rank: Super Contributor
timestamp: May 19, 2020, 02:05:36 am
content: Constant current thats adjustable saves components.You can set it to limit the current of a device to approximately what its expected to draw plus 5 or 10%. So that may mean you need 4 or 5 digits instead of 3.Almost any adjustable voltage adjustable current limit supply thats moderately accurate is much better than using generic wall warts or any non current adjustable supply for building stuff. You can build a suitable supply for just a few dollars with one of those buck or buck boost converter modules.The power supplies you linked are all way out of my price range and also - if I was going to spend that much I would get something like what I have now, for my main power supply I have a 35 year old Sorensen XT triple supply that i bought "for parts or not working" on ebay for $65 figuring that it would be repairable and it was. Its very heavy, though, and it hums a little bit, But its output is very very quiet and its very adjustible. I don't need 20 amps, if I want more current I can strap my power supplies (its actually 3 supplies in one) together. What I love is very fine grained control over both current and voltage and its very accurate. If I was going to spend that much I would get a fairly new, used power supply from one of the UK's well known brands, I would use availability of service manual as a big factor too.Since you are in the UK. you might be able to fid a well reputed local brand, like TTI, used or at an auction.Also, its nice to have a visual as well as audio indication when current limit trips.

author: christopher iles
author_rank: Regular Contributor
timestamp: May 19, 2020, 11:00:31 am
content: Hello,I've been using a Manson 25 amp supply for ten years without problems.It's 0-15v 25 amps and cost £99 new.They are linear, not switch mode and in my opinion superior.I do not like switch mode power supplies at all. noisy and unreliable.Hope this helps,Kind regards,Chris.

author: mathsquid
author_rank: Frequent Contributor
timestamp: May 19, 2020, 06:03:38 pm
content: Quote from: cdev on May 19, 2020, 02:05:36 amWell said.When I first got into playing with microcontrollers, I powered everything with 9V or AA batteries, and I didn't have any problems with cooking components. Then I built a CNC controller and powered it with a computer PSU that could source something like 30 amps at 5v. I fried two LCD character displays from being less than careful when hooking them up. It was a learning experience.