[xkadet]

I have a nice linear 42V pwer supply that I want to run my cnc controller system with and I wondered if any of the electronically inclined out there could give me some tips on the best way to take the 42V DC output and pull off 5V (2amps) and a 12-30V (5amps) legs. ( I need these legs to be stable and not likely to introduce spikes, ripple, or other anomalies into the circuits--this is a priority! so don't be afraid to suggest caps and filters where needed) I know that you can use linear voltage regs like the 7805 and the LM 317 but these are rated for less voltage than my linear supply provides. I also have heard that you can reduce voltage stepwise by adding diodes in series. However, this is not what I'm looking for because to reach 5 v from 42... well, you know. So I am aware of some less than ideal options but I'd like to do this right so I need some experienced and seasoned advice here, if someone would be so kind to provide it. I have a great deal of current and olders linear and digital components that I can pull from to do this project so don't be afraid to suggest unusual components or approaches.
all of this is a learning experience.

Best regards and thanks in advance for any and all help.

Keith

[doorknob]

I don't have a specific suggestion, except to note that doing what you want to do with linear components is unlikely to be an efficient approach. You would end up with a nifty heater, but not as nifty of a power supply.

So I honestly think that you'd be better off to build or buy separate transformer-operated linear supplies to get the auxiliary voltages that you need rather than restricting yourself to tapping off of the 42 volt supply. If you really do insist upon using the 42 volt supply to derive the other voltages, then you will probably be best off to find some DC-to-DC switching converter modules of some sort to do the job.

[Al_The_Man]

You did not mention if it was a regulated linear supply or not?
The way I normally do it is to purchase a Toroidal transformer with the correct main winding and wind on the auxiliary windings on as needed and if necessary fit the 78xx regulators on the suitably wound secondaries.
Al.

[mike_Kilroy]

maybe ebay is your friend? 12v 5a sounds like a little CB radio power supply - rob avail already built and fused with line cord for $ 8

5v 2 a sounds like a little wall wart that would sell complete for $ 3