Question

In a transformer, the power is a constant either ends. Why?

Answer 1

If it is a voltage step-up there is a corresponding step-down of current so the product is very close to being the same. There will be some loss as a transformer is not 100% efficient. If it is a step-down voltage there will be a step-up with regard to current and remember, it is the product of voltage and current that equals power.

Answer 2

But why is there a corresponding step-down of current?

Answer 3

for the conservation of energy. If it was the other way around, the transformer would become a generator, you could sell the produced power and make a million.

Answer 4

Power in will be equal to or a little less than power out. That is why.

Answer 5

So could you say that the resistance of the secondary coil in/decreases to match the change of voltage/current?

Answer 6

I wouldn't say it that way. You realize of course the actual current will depend on the load connected to the secondary, and the capacity of the source power.

Answer 7

What kind of statement are you required to make?

Answer 8

What you did say might be appropriate if you used the term impedance. A transformer will transform current, voltage, and impedance.

Answer 9

all at the same time! lol.

Answer 10

Thanks, that’s exactly the kind of thing I was looking for.

Answer 11

So it's essentially 'AC resistance' to put it crudely?

Answer 12

1:2 transformer will double the voltage, halve the current and present an impedand of 1:4 (I think it is the square of the turns ratio) (my memory is not the best lol)

Answer 13

I believe you have come to terms with an explanation that suits you and explains it for you. Good luck in your studies.