Linear power...

Hi,

I am looking to build a linear power supply for a project of mine and I need a +5, -5, +15 and -15 supply. It was suggested that I use LM338t's for each but the 338t does not list it for use as a - regulator. (I am some what green at this) Anyhow am I missing something? Is there a way I can make the - supplies with the 338t?

Thanks

God bless....

Mark
 
Hi,
you could also use 317/337 for +- supplies.
However you can cascade two positive supplies connecting the +ve out of one to the negative output of the other and using this common as your earth/ground/common return.
To do this you need two separate windings on your transformer and then two separate rectifiers. Do not common any of the wiring before the outputs of the regulators.
I hear that the performance of the +ve reg. is better than the -ve and that this cascading gives an overall improvement.
I have never built one but coming soon.
You could assemble a much cheaper 5A supply if you used a 1A or 1.5A reg. with booster transistor or FET as shown in the data sheets.