# voltage changer

Discussion in 'The Projects Forum' started by rakesh696, Jan 2, 2009.

1. ### rakesh696 Thread Starter Member

Dec 15, 2008
10
0
i need a circuit of different voltages (dc)
input 12v dc 5A .....output ll b +12V 5A ,
5V or 6V 2A ,
0V
-12V 2A ,
-6V 2A

Apr 5, 2008
19,908
4,138
Hello,

Your output power is larger than the given input power.
This is impossible. For all the voltages you require you will need more input power.

Greetings,
Bertus

3. ### SgtWookie Expert

Jul 17, 2007
22,201
1,809
Input:
12vdc 5A

Output:
12V @ 5A
5V to 6V @ 2A
GND
-12V @ 2A
-6V @ 2A

As Bertus says, you can't get out more power than you put into it. If you could ever figure out how to do that, you will be a very rich person indeed.
You say you want the source to be 12v @ 5A, yet your very first output is 12v @ 5A. This could be done by using a straight piece of wire with a 5A fuse in it, if you did not require voltage regulation.

If you require regulation for the +12v, you will have to use something like a buck/boost switching regulator, which will be somewhere between 80% to 95% efficient. This also means that since power will be consumed in the regulation process, you will have to have more current coming into the circuit than will be going out.

The other voltages could also be created using switching buck regulators, the -12v, -5v would have to be an inverting topology. These would be somewhere around 85% efficient, so you will require more power in than you will get out.

4. ### rakesh696 Thread Starter Member

Dec 15, 2008
10
0
tnk u for clear xplanation of power consumption ..
ill tr dat in alternate circuit