Tell me about your dream power supply!

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Austringer
 
Posts: 4
Joined: Wed Mar 05, 2008 12:55 am

Tell me about your dream power supply!

Post by Austringer »

I've been getting by on various and sundry wall warts and batteries for my electronic dabbling, but now I actually have to diagnose and fix something (a $400 furnace control board that has, maybe, $15 worth of components on it) and it wants 24 v AC, so here's my excuse to build myself a decent power supply. Knowing that beginners often go after all the wrong features in tools, though, I thought I'd ask here and see what people who really knew this stuff would make sure they included if they were building from the ground up.

This wows me http://tuxgraphics.org/electronics/2010 ... y-v3.shtml, but I'd like to add constant voltage binding posts for the most common voltages (at least +/-5 and +/-12) and a set of 12 and 24 V AC posts. Does this make sense? Is there any point to trying to condition the AC at all (and could I even afford to do it on a reasonable budget) or should I just shove a transformer in there with the right taps for what I expect to come out of the wall and call it good?

uoip
 
Posts: 127
Joined: Wed Sep 23, 2009 5:48 pm

Re: Tell me about your dream power supply!

Post by uoip »

That tuxgraphics supply you linked to looks nice.

I've never had a need for much low voltage AC, but if I were diagnosing something that required it, I'd probably just use an appropriate transformer.

I have a constant 12V regulated supply and a 5V supply that sit in a fairly inaccessible place under my bench, with wires up to my bench. The 12V supply goes to anderson power poles and BANNED lighter jacks, as well as banana jacks. The 5V supply goes to banana jacks and USB sockets.

Those constant 12V and 5V supplies are useful for powering little gadgets (fans, USB chargers), but I don't need to clutter up the top of the bench with them, since I never need to adjust their controls. My workhorse supply that sits on the top of my bench for most use is a fairly standard adjustable bench supply.

The standard bench supply features are very useful. Adjustable constant voltage, adjustable constant current, short circuit protection (goes into constant current mode when a short is presented to it), panel meters that always display voltage and current.

The most valuable feature that's missing on many supplies is a high quality 10-turn pot to give easy and precise voltage adjustment. I can live without it on the current adjustment, but it's very useful on the voltage adjustment. This may be irrelevant if you're using the digital controls as described in the kit you linked to.

I'd usually rather have 0-18V with precise adjustment than 0-36V with less precision.

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easternstargeek
 
Posts: 347
Joined: Mon Dec 13, 2010 1:39 pm

Re: Tell me about your dream power supply!

Post by easternstargeek »

If you need 24VAC, go to the local home center and pick up a 24VAC thermostat transformer. You'll find them wherever fine thermostats are sold (Try the Plumbing or Electrical department.) The little 18VA units go for around $9.00 the last time I looked.

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