Need power supply design - +-12V 1A and 0-30V 1A

[rohit.p]

hii

i wnt +-12V 1A and 0-30V 1A both in only one ckt.....
if any one having its complete ckt digram pls snd...

 

[thebadtall]

hello there .

you can use one transformer with +/- 12v ac, wich you can connect the leads without center tap, rectify it and get 33v dc, then you can use adjustable regulator lm338k or lm317 to regulate it down to 1.25v

also you will need to rectify the +-12v and you will get around 16vdc.
if you want a constant +-12vdc you need to regulate both rails , using lm337negative voltage regulator and lm317 positive regulator, both are adjustable so you will be having a range of +-14v but will have to have a dual taper adjustment potentiometer

i cannot draw you circuit at the moment but it is not difficult. would you like to operate both voltages the same time?

 

[BradtheRad]

A 15-0-15 center tap transformer can give you 30V if you use the entire winding (as thebadtall stated).

The same center tap transformer can also give you + and - 12V. The center tap is zero ground. You would regulate them using regulator IC's.

However then you would not have your 30V supply referenced to the center tap.

Do you want the +30V to be referenced to the same zero ground? This could be done with a symmetrical voltage doubler.

Schematic using Cockcroft-Walton design:

 

[rohit.p]

ya... i wnt to operate both vltgs at the same time... and also m tryng to add display to it...

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thnks bradtherad... bt it not enough for me..i wnt +-12v and 0-30V VARIABLE vltg... so pls guide..