Electronics > Beginners
All about Linear Power Supplies
queennikki1972:
--- Quote from: MarkF on April 26, 2019, 01:43:02 am ---At a minimum, use a heatsink similar to a RA-T2X-64E with a fan.
(Check that. Your big aluminum one looks good but you will probably need a fan.)
--- End quote ---
By fan, do you mean directly on the regulator or a case fan (exhaust fan in the rear of the case)
MarkF:
Anything to circulate air across the heatsink.
Remember, the largest power it will need to dissipate is at low voltage and high current output. The LM317 or bypass transistor has to drop the largest voltage at that point and still provide a high current. Power(P) = voltage(V) * current(I).
MarkF:
Food for thought...
Here is a small PCB I did for a LM317 adjustable supply (no current limiting) based on the datasheet.
Input is either a wall wart or a transformer.
digsys:
It all about thermodynamics ! The more "efficiently" you set it up, the less air you need across the heatsink.
Ideally - either mount the fan to the Top of the HS and suck air UP, out of the enclosure - Hot air rises. Or mount to the bottom and blow up, pulling in cold air
from the outside. You can just "blow into" the HS, or just suck "out of" the enclosure - it all works, but efficiency will vary.
As long as the "hot air" is expelled, pretty much anything works. At your currents / voltages, it's not a big deal.
It gets "serious" when the power levels go up dramatically -
This is an E-Load I make for discharging EV battery packs - https://pbase.com/digsys/image/158741423
It can "push" 2,000W at peak. I have high-flows pushing and pulling, with added turbulence. If we need to run for hours, I'll jam 2 fans each side !!
queennikki1972:
Wow! both are impressive. I have not learned to draw or etch boards yet. I started with a few simple circuits like police lights and piezo alarms and then dove right into power supplies. I am still learning the math but its difficult to search for the formula if you dont know one exist yet :P :-\
I appreciate all the help.
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