7805 heat?

shmagoogin77 · Post by **shmagoogin77** » Mon May 01, 2006 6:39 pm

i am using a 7.2v 3300mah battery for my SNESp
the 7805 going to the snes is on a heatsink and still seems to be getting way to hot for only 7.2v
any thing wrong with this??

Post by **SpongeBuell** » Mon May 01, 2006 7:24 pm

don't worry, the 7805 is made to be hot, it converts all excess voltage into heat. A normal heatsink should do ya fine, just don't put it near some gasoline or something

shmagoogin77 · Post by **shmagoogin77** » Mon May 01, 2006 7:36 pm

i know it converts it to heat but i always thought that if the voltage was lower that the heat would be less

daguuy · Post by **daguuy** » Mon May 01, 2006 7:54 pm

and it's only using a few hundred ma, maybe it's an older less heat efficient 7805. don't worry about it but if you want, you could replace it with a 5v dc-dc convertor or LDO

Post by **Skyone** » Mon May 01, 2006 8:18 pm

A 7805 can handle 1A or 1.5A depending on it's manufacturer. If the 7805 needs to give out more than 1A/1.5A to the component need power, it will most likely break.

joevennix · Post by **joevennix** » Mon May 01, 2006 8:52 pm

Try using a better converter, like one from TI
It may take up a bit more room, but in the end its worth it...

shmagoogin77 · Post by **shmagoogin77** » Thu May 04, 2006 8:32 pm

so i cant use the 7805
where can i get a better converter
link to one??

daguuy · Post by **daguuy** » Thu May 04, 2006 8:38 pm

http://focus.ti.com/docs/prod/folders/p ... st105.html

shmagoogin77 · Post by **shmagoogin77** » Thu May 04, 2006 8:43 pm

the lowest one has a min. of 9v in and my battery has 3.3 amps

daguuy · Post by **daguuy** » Thu May 04, 2006 9:00 pm

i have one of these, it works at 7.2v. you might need a little inductor for the input because it does make some ripple on the input line. as far as i know, it works at even lower voltage than 7805. it's also more efficient and makes less heat

shmagoogin77 · Post by **shmagoogin77** » Sun May 07, 2006 6:32 pm

but i can still use the 7805?
how big is the converter??

Post by **Skyone** » Sun May 07, 2006 6:35 pm

Oh, you can also use the TI PTH08000 or PTH08080 for the job.

shmagoogin77 · Post by **shmagoogin77** » Mon May 08, 2006 7:58 pm

but my 7805 should work just fine right?

joevennix · Post by **joevennix** » Mon May 08, 2006 8:15 pm

Of course it will work fine, until it overheats. Add a larger heatsink or something: fabricate your own.

blackbox_dev · Post by **blackbox_dev** » Tue May 09, 2006 6:55 am

No one can resist my red hot heat!

Sorry, I couldn't resist.

Basically, when you supply higher voltages and need more current out of the 7805 you should heatsink it. Without it, the 7805 will shutoff after it overheats to prevent it from frying.