How do transformers filter?

[calebgriffith]

How do transformers filter? Do they function the same way as inductors?

[Jonathan Bright]

Transformers are not usually seen as filters. As their name implies they "transform" things and in most cases it is the level of voltage that is altered. So that the AC from the mains supply (in the US 110-115 volts ac) is put through a transformer and comes out at a lower level for use in the appropriate equipment. (it can of course be used to step up a given voltage in other situations). Some Inductors and transformers share some characteristics such as wire wound on metal but they are different. Your post was asking about filters. Now many pieces of equipment have the following set up. There is a transformer to alter the voltage. Then a rectifier to change it from AC to DC and this is generally followed by some sort of filter to smooth the supply. This is often a capacitor, it can involve capacitors and solid state devices to get accurate levels and some supply filters use inductors and capacitors in combination. It always helps to get the basic principles clear and in this case the best bet would be to check out the two terms in a basic book on electronics. Putting them in Google would be a start. The local library would have some material in the 621 section. You obviously have a reason for posting this question. You might get a better response if you told us why you were making this enquiry.

[Stocker]

You mean a mains voltage transformer? They are magnetically coupled, with inherently low bandwidth... is that what you mean?

[darkfenriz]

Originally posted by calebgriffith
How do transformers filter? Do they function the same way as inductors?

basically yes

[DIYdo]

I think you may be asking how power output from a transformer coupled OPS drops with increasing frequency. Or how transformer coupled stages and balanced lines have a limited bandwidth with a high frequency rolloff.

Then as allready said, basically yes!

[CBS240]

Transfomers have internal impeadences or reactance that can be a filter to certain frequencies they are not designed to 'transform'. This is basically related to coils of wire, magnetic flux saturation, copper losses, ect. Side affects of construction I suppose.

[lndm]

Originally posted by calebgriffith
How do transformers filter? Do they function the same way as inductors?

Transformers are very similar to inductors but they are used differently.

You could use a transformer as an inductor, but you normally wouldn't.

A power transformer isn't used for filtering in the way you normally use it.

P.S. a simple transformer is made of two inductors mutually magnetically coupled.