7809....which regulator for 100ma or less? (to-220 or 92)

[sjaltenb]

im building about a dozen power supplies, 12vac to 9vdc... Each PSU will only supply 1 effect so usually its only around 5ma each
(fuzz, overdrive, two compressors, a rat, muff, ce2, tr2)

anyway, do i need to use a TO-220 case with the 1amp rating or can i get away with the .1ma rating on the TO-92 package. This whole board is based on doing things overboard, so i don't mind using the bigger one or anything like that... Just wondering if there is ANY difference if im only pulling 20-30ma max.

Either way, i figure the To-220 will not need a heat sink because I am cutting the mains voltage close as is, and there will not be much pull...

suggestions appreciated!

My PSU design right now is:

12vac@100ma-->Bridge Rec-->Large filter cap (1000-4700uf or so)-->.1uf-->7809reg-->100uf-->.1uf-->9v out

[The Tone God]

If you only need a 100mA then go with the TO92.

Andrew

[Paul Perry (Frostwave)]

12V ac gives 12x1.4=16.8 v peak.
So that is about 7 v drop across the regulator. So that is 30mA x 7V = 210mW. Maybe a little more than you were expecting!