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DIY power supply
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Cliff Matthews:
Hard to understand why TO220 338's exist.. what good is the 5amps when internal thermal protection limits the whole package to dissipating ~15watts on an ideal heat sink. Seems LM317 and 337 are fine with additional pass devices..??
For the OP, maybe someone can comment on the schematic half-way down on this link:
https://electronics.stackexchange.com/questions/186760/why-do-linear-voltage-regulators-have-minimum-output-voltage-0-v
JS:

--- Quote from: Cliff Matthews on September 02, 2018, 01:10:48 am ---Hard to understand why TO220 338's exist.. what good is the 5amps when internal thermal protection limits the whole package to dissipating ~15watts on an ideal heat sink.

--- End quote ---
Why do you say so?
At 0.7ÂșC/W it's better than the TO3 package, the thing is the TO3 package has a bigger plate with two screws so the thermal resistance case to heatsink can be made lower, plus the bigger thermal mass can make it handle higher peaks better.

Still, if what you say it's true it could work in a 3V dropout application, which it can do over the whole temp range.

JS
Pirateguy:
well wouldn't u know it, the thrift store no longer has the ATX i saw, nor much of anything else PSU wise.
i guess ill have to take inventory of the wallwarts n stuff i have...
Pirateguy:
scored an ATX!

Pirateguy:
the new plan:

from the wall:

ATX:

polyfused 3.3v
polyfused 5v
polyfused -5v (7905 from -12v rail)
polyfused 12v
polyfused -12v
USB (from 5v SB)
-variable (DPS3012, from 12v rail)

on the front panel:

Thermometer with sensor broken out to binding posts. link
Thermostat controlling the fans link or link
Func gen. link
Relay timer link
usb tester link

also i think i will add a double wall socket with a dimmer on one of them, and add a halogen ballast with 2 outputs, of which one has a dimmer.

and on the wall sockets i will have this:
AC volt/amp meter link

also since i cannot find a nice box to built it into, i found some help for making a custom box out of multiplex or something like that.

also i may want to put an adjustable load in there at some point, but i need to learn more about them.
am wondering if it might be better to keep that separate cuz of temperatures? seems like that kinda thing would get hot...?
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