PDA

View Full Version : How transformers work ?


tusharm94
Feb 15, 2010, 11:12 PM
In a transformer when we pass current I at a voltage V, it induces current I' in secondary coil at some V' . Here the VI=V'I'. Now I am confused that in a way is energy not being "created"(which is not possible). The reason I am saying is while stepping up or down electrical energy of current in primary coil is not used or transformed and still current of same Power is induced. While I know how it's induced , I want to know is energy in a way not being created. Please help

TommyBotham
Feb 16, 2010, 02:53 AM
Magnetism baby.

A current flowing in a primary coil will produce a magnetic field and cause a current to flow in the secondary coil. The primary current coil is effectivly the voltage of the secondary coil.

However, the magnitude of the voltage in the secondary coil depends on how many turns the primary coil has. B = (mu)IN

Where B = magnetic field
Mu = a constant
I = Current flowing through primary coil
N = number of turns of coil.

In any case, energy will never be created out of nothing, it just depends on how much you want to step up or step down the current in the secondary coil.

I gave a pretty leyman explanation by the way.

KISS
Feb 16, 2010, 03:39 AM
By saying VI=V'I' your saying that VI=V'I' = k.

Hence power in = power out.

In reality power in is > power out since there are losses such as eddy current and magnetic coupling which can be ignored. Transformers can get warm. Wires vibrate for one.

If you have (120)(1) = (30)(4); power is constant.