Question

a portable radio has a built in transformer so that it can work from the mains instead of batteries. is this step up or step down transformer? give reason. ​

Answer 1

Answer:

Explanation:

Answer to some of your questions:

We know,

Reactance of an inductor, XL = ω L = 2πf (μoμrn2lA)

Using the above expression,

For radio frequency (high frequency) the reactance will be large even for μr =1. That is why radio frequency choke is air cored.

For audio frequency (low frequency) the reactance will be small if μr =1. So to increase the reactance an iron core is inserted (μr is large) that is why the audio frequency choke is iron cored.