LM7809 voltage regulator quick question

[Pauld35]

hello,

after shorting my reasonably good quiet dc/dc stepdown ps,
I cut up my hitachi torch and attached it to my ps so it now takes the battery packs from my battery drill for use with 9v effects and bread boarding stuff.

i was rushing it and blew up another cheap dc/dc stepdown with reverse polarity when i wired it up.......so i went for a real cheap dc/dc stepdown and it introduces a slow osolating noise into the pure dc from the battery and does the same when from a mains adapter.

Could someone tell me if a LM7809 voltage regulator 1.5amp will introduce noise if i run dc from a battery through it?

thanks

 

[rayma]

Could someone tell me if a LM7809 voltage regulator 1.5amp will introduce noise
if i run dc from a battery through it?

It shouldn't, so give it a try. Use two 10uF 25V electrolytics, connected close to the input and output pins.
The input voltage will have to remain above about 11V, though.

 

[dotneck335]

For the least noise, use the ON Semiconductor LM7809s--they seem to test better than the others.