combining power regulators

[birt]

Can i use a 12Vdc regulator and a 9Vdc regulator on the same DC line?

i mean in a way that i have the full 1A at 9V and also 1A at 12V. i know it works if i use the 9V regulator after the 12V but then i will have 1A in total instead of 2A.

[George Giblet]

Yes it will work, in fact it is probably the more common way to do it.

You just have to be careful the 9V regulator doesn't get to hot under full load.

Assuming a 16V DC input the 12V regulator will dissipate (16V-12V)*1A = 4W, but the 9V will dissipate (16V-9V)*1A = 7W.

If you connect the 9V regulator and draw 1A from the 9V (nothing from the 12V) the 12V regulator will dissipate 4W as before but the 9V only dissipates (12-9)*1A = 3W.  So the 9V regulator dissipates more in this case.  Note however in both cases the total power dissipated when drawing 1A from the 9V alone is the same:  first case 7W from 9V reg, second case 4W from 12V and 3W from the 9V ie. 7W total.

[birt]

thanks! i'm gonna use a 16V laptop battery to make a pedal board power supply.

[ambulancevoice]

put each regulator on its own heatsink too
not the same heatsink together, there own one each