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Re: -5V on IIgs
On Mar 5, 1:10 pm, "James Littlejohn" <nargut...@yahoo.com> wrote:
> Can I use the 7905 between the -12v and ground output to achieve -5v?
Probably. The Apple IIc does it that way for the tiny amount of -5V it
requires. The more current you need the less efficient a linear
regulator solution is going to be. Try measuring the -5V current on a
IIgs and see how much it needs.
> And efficient will this be with a .25A ?
The 7905 will have to dissipate at least 7V * 0.25A = 1.75W which is
wasted as heat.
> If my load is small or non
> existent does this still eat up a lot of power in the 'standby' mode?
No - zero current out will be the best situation for keeping the 7905
cool.