Transformers, its current and its resistance

by Taturana
Tags: current, resistance, transformers
Taturana is offline
May5-12, 10:35 AM
P: 109

Suppose a simple transformer, not connected to a circuit (just to the home AC). If we get a multimeter and measure its resistance we will get a number. So if we plug it into the home AC, it will consume energy (constant power).

Now suppose we have a desktop computer power supply. Well, the desktop consumption varies: if we are playing a game, the video card is dissipating more power etc. So, I would imagine that if the desktop consumption raises, the desktop is not only consuming more from the power supply, but the power supply is also consuming more from the home AC, otherwise it will be a really huge non-optimized solution for power supplies. But I also know that the only thing connected to the home AC (if we look the power supply circuit itself) is the transformer, which is, in essence, an inductor (but acts like a resistor, it's a lot of cable, it has a resistance).

Given this, the main question is: if the unique thing connected to the home AC is the coil of the transformer, and this coil has a resistance, which lets a I current flows, how could the power supply consume less or more power from the home AC?

I think you all understand my question. Please, could someone give me a clear explanation on that?

Thank you very much
Phys.Org News Partner Physics news on
Information storage for the next generation of plastic computers
Scientists capture ultrafast snapshots of light-driven superconductivity
Progress in the fight against quantum dissipation
Drakkith is offline
May5-12, 08:43 PM
PF Gold
Drakkith's Avatar
P: 11,005
I can't do a detailed explanation as I don't know enough, but I believe that the different items that are consuming power in the secondary windings circuit cause various levels of resistance in the primary circuit through counter EMF.
russ_watters is offline
May5-12, 08:58 PM
P: 21,998

Register to reply

Related Discussions
Resistance in a circuit with transformers Introductory Physics Homework 13
Effective resistance of secondary circuit in transformers Introductory Physics Homework 2
Current Transformers Electrical Engineering 2
Question About Current Transformers Electrical Engineering 8
Transformers and induced current Introductory Physics Homework 3