How many power supplies?? - Page 1
Forum section: electronics / beginners

author: Ranger14
author_rank: Regular Contributor
timestamp: January 23, 2017, 03:36:09 am
content: I have been repairing electronics for a long time.. But lately I have trying to learn electronics in my spare time.. So my question in everyones experience how power supplies do you need in say a home electronic station/shop??

author: Ian.M
author_rank: Super Contributor
timestamp: January 23, 2017, 03:53:56 am
content: That very much depends what you are doing. It isn't so much how many power supplies as how many different power rails you need at the same time and their capabilities.Typical requirements when messing around with:* logic, Arduinos and other MCUs :- 5V and 3.3V 2A (adjustable current limit)* OPAMPs :- +/- 9V to 18V, 1A (adjustable current limit)* motors and actuators +12V or +24V, amperage dependent on loads. Other voltages may be needed if you are developing LiPO powered kit.* CB, Ham Radio and automotive gadgets :- 13.8V DC 10A (bench power for in-car kit)and of course everyone needs at least one 0-30V 1A supply with adjustable current limit, for when you need an extra bias rail.All-in-ones multiple output supplies are $expen$ive$ and frequently have limitations like seperate channels sharing a common 0V which limit how you can combine their channels. Seperate supplies are often more cost effective . . . .

author: ziplock9000
author_rank: Regular Contributor
timestamp: January 23, 2017, 08:28:19 am
content: I'm at the point now where I need a second supply. The Farnell one I have is good, but it's single rail. So I'd say for general use, 2 PSUs or one with two rails (-/+)

author: james_s
author_rank: Super Contributor
timestamp: January 24, 2017, 05:04:39 am
content: You can never have too many power supplies, but as has been mentioned already it really depends on what you're doing. Most of mine are self made, I have several in the 0-30V range at 2-3 Amps, a fixed 12V 3A unit, a fixed 5V unit, then there's a rectifier/filter I plug into my variac, and then if I really need a lot of juice for something I have a couple of 12V 55A server power supplies that I isolated the DC ground so they can be wired in series if needed.

author: digsys
author_rank: Unknown
timestamp: January 24, 2017, 05:07:43 am
content: Just make sure that you have at least ONE Linear and ONE S/Mode. There are often times when you can't substitute one for the other (within reason).

author: bitseeker
author_rank: Super Contributor
timestamp: January 24, 2017, 07:41:00 am
content: It really depends what you're learning or repairing, and how many different power requirements you need to fulfill simultaneously. Ian covered the common scenarios, but requirements can vary greatly as electronics covers so many areas.Since you've been repairing electronics for a long time, how many power supplies and of what types have you used for that? How does, or will, the electronics you intend to build differ?If you're really unsure what you'll be doing, then you can start off with a typical triple-channel power supply (e.g., 2x 30V@3A, 1x 5V@3A, with support for serial/parallel operation) and see what you end up needing as you figure out where your electronics interests lead you.

author: jeroen79
author_rank: Frequent Contributor
timestamp: January 24, 2017, 11:00:18 am
content: Quote from: digsys on January 24, 2017, 05:07:43 amWhen would a linear supply be unsuitable and a switchmode required?

author: digsys
author_rank: Unknown
timestamp: January 24, 2017, 11:27:29 am
content: Quote from: jeroen79I have 1-60VDC @ 30A and 50A S/Modes, also 10-220VDC @ 15A - An almost impossible ask for linear, not forgetting the weight and heat involved.Step responses are also faster, when running under program mode. For that power, much more readily available and cheaper (and lighter).My largest linear is 2x 0-30V 5A, and it's huge / heavy with quite noisy fans. I use it when I must have absolute clean (quiet) ripple, or can't afford ANY current over-shoot.Edit: Most S/Modes also have at least some sort of programmable OP function capability.Linear: If I'm testing a 3V3 / 5V ULP instrument opamp with 10-12 bit ADC or 0-10mV current sense, S/Mode is pretty useless (even with a linear reg added).