I am making a Ckt, in which I want 9 volts D.C output bt m Getting 125 Volts.
Is there any method to control the D.C voltage at the min. cost level

Is the 125 Volts AC or DC? If it is AC, you will need a step down transformer and a rectifier. Radio Shack carries a large assortment of these devices already built into 1 plug in.

No, It's a D.C Voltage of 125 Volts.

I would run the AC voltage through a Full Wave Bridge(4 diodes) an an Electrolytic Capacitor to smooth the ripple.
What are you trying to power?
Edit, if you need 9 volts, you will need a step down transformer as mentioned.
What is your current circuit?

This is easy and does not have to be complicated. Go to Radio Shack or Walmart and purchase one of those little "Wall Bugs".. ya know, like you use to charge your cell phone. They come in all voltage and current ratings so have the info when you go to get one.

Mr Handyman, you sound average. My red and this post is in response to the red you gave me above.

A couple of things, it sounds like he needs a 125 volts DC, Not 9 volts DC, in which case, it would not be your "wall bug".
Also they haven't answered on the "Current" requirement(50 Amps?).
And until they answer, they might even mean, getting 12.5 volts down to 9 volts.
You don't HAVE to give a RED because it is too complicated, Actually it is about the simplist of circuits, and can be used with most Voltages and currents.
Presently, I don't know what they want, and if it will just plug into an outlet?

To the original poster. If you can provide exactly what you are trying to do, we may be better able to answer your question more effectively in terms you may understand.OK?

Ok,, you want to reduce 125 VDC to 9 VDC . A reasonable way is to build a voltage reduction circuit. Just use Google to search for one.

Uhhh... Handyman2007, now who's being too complicated? I have built electronic circuits in the past, and to get something that will regulate 125vdc down to 9vdc (no idea of the current required) is not just "Google to search" and "build" it. This could be DANGEROUS unless a person has some knowledge and experience, and if they did, they wouldn't be asking questions here.

I for one will not offer any help here because there are too many unknowns and too much that could be dangerous. The original poster should look to buy a product off-the-shelf that will do the job needed.

Can you explain what you currently have?
A couple of us here can give good solutions, but NEED some info, can you help?