AC/DC Voltage

Thread Starter


Joined Apr 30, 2005
Hello everyone..
I am new to this forum(first time post)..
I have several questions I would like to ask and I will start out with the easist one first You guys(ladies) will probably think "jeesh" what an idiot...
I know that when you take an AC voltage and step it down your current increases..
Does this apply to a DC voltage as well??


Joined Jan 24, 2005
well, typically no, I dont think that you can use a transformer on dc. When you step down DC voltage you release alot of heat. Hopefully some1 can give you some better clarification or fix what I have said ;). Hope this helps.



Joined Apr 20, 2004

You are dealing in the area of power to a load. If you are supplying AC power through a transformer, your example is easy to demonstrate. A 12 volt secondary supplying 10 amps of current will measure 120 volts and one amp of current on the primary side. The primary is taking 120 watts of power and passing it to the secondary side.

But lowering the voltage does not automatically raise the current - no such relationship between voltage and current exists. Think of opening the secondary circuit in the example above. There will be the stepped down voltage in the secondary, but no current.

With DC, any methodology that reduces voltage also wastes some power, so that a reduced DC voltage always means less current than on the supply side.