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using wal wart to make variable voltage power supply

Kerazyugy

Nov 1, 2013
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Ok guys I'm trying to make a "bench top power supply" my first electronics project

I have a wal wart (Out31.5v 3.17a) I've been trying to figure out how to use a LM317t voltage regulator but have been told that 3.17a is too much for this regulator i'm hoping to get atleast 24v at 3 ohms at a max .... (im only going on these figures based on some googleing about what you should have as a frist psu) is there a way of doing this? or am i asking for too much (note i'm mostly goofing around with arduino stuff some motors led's lcd's sensors and stuff like that....
thanks in advance
p.s. sorry if this is a super basic question i am a super noob :)
 

davenn

Moderator
Sep 5, 2009
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hi there

have a look at a LM338 regulator instead, use the metal (steel) cased TO3 style, its a 5A adjustable regulator :)
make sure you mount it on a decent heatsink!!


Dave
 

BobK

Jan 5, 2010
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Ok guys I'm trying to make a "bench top power supply" my first electronics project

I have a wal wart (Out31.5v 3.17a) I've been trying to figure out how to use a LM317t voltage regulator but have been told that 3.17a is too much for this regulator i'm hoping to get atleast 24v at 3 ohms at a max .... (im only going on these figures based on some googleing about what you should have as a frist psu) is there a way of doing this? or am i asking for too much (note i'm mostly goofing around with arduino stuff some motors led's lcd's sensors and stuff like that....
thanks in advance
p.s. sorry if this is a super basic question i am a super noob :)
Did you really mean 24V at 3 Ohms? That would be 8 Amps. Also, that must be one massive wall-wart if it outputs 31.5V at 3.17A.

Bob
 

davenn

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Sep 5, 2009
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Did you really mean 24V at 3 Ohms? That would be 8 Amps. Also, that must be one massive wall-wart if it outputs 31.5V at 3.17A.

Bob

naaa I'm pretty sure he meant 24V at 3Amps :)

Dave
 

BobK

Jan 5, 2010
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Ohms, Amps, what's the difference?

Bob
 

eKretz

Apr 8, 2013
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Did you really mean 24V at 3 Ohms? That would be 8 Amps. Also, that must be one massive wall-wart if it outputs 31.5V at 3.17A.

Bob

LOL, probably more like a floor wart.
 
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