Measuring insertion loss of transformer

[fstspec]

Can anyone explain to me how do you determine which side of the transformer is the high impedance winding side. Is it always the secondary side and the low impedance winding is the primary side?

 

[Nigel Goodwin]

Can anyone explain to me how do you determine which side of the transformer is the high impedance winding side. Is it always the secondary side and the low impedance winding is the primary side?

Simply measure it's resistance, the higher impedance side will also have a higher resistance.

The primary is not always the highest, that's only for a step down transformer, for a step up transformer the secondary will be highest.

But the vast majority of transformers are step down, so almost always the primary will be the highest resistance.

 

[Papabravo]

Not all transformers are power transformers, and I've never heard of insertion loss with respect to power transformers. Insertion loss is frequency dependent. Inductors and transformers have an upper limit on the frequency where they still behave like inductors and transformers. So which kind of transformers are we talking about, and what is the application in which you are interested?

 

[Optikon]

I agree with you papbravo..
I have in my hand a high frequency ferrite toroid with ONE turn for the primary and ONE turn for the secondary. Which side is high impedance?
At 5MHz it's the same.

 

[Nigel Goodwin]

I agree with you papbravo..
I have in my hand a high frequency ferrite toroid with ONE turn for the primary and ONE turn for the secondary. Which side is high impedance?
At 5MHz it's the same.

Presumably a 1:1 ratio transformer will have identical resistance/impedance windings?, so it makes very little difference which is which - except there may be specific reasons to use one as the primary for safety reasons?.

 

[Analog]

Presumably a 1:1 ratio transformer will have identical resistance/impedance windings?, so it makes very little difference which is which - except there may be specific reasons to use one as the primary for safety reasons?.

could be due to insulation differences between the windings.