question about switching transformer.

[simpsonss]

Hi,

From what i know for transformer, there is coil winding inside. If i use a DMM and turn to short-circuit testing mode and then i measure two of leg from the secondary side.If it is short circuit,is it means that it is from a same winding?

For example, if leg 1 and leg 2 is short circuit. So is it similar to the diagram below?

---------------- 1
(
(
(
---------------- 2

 

[BrownOut]

If you measure across two wires connected to the same coil, you'll get a finite resistance. If the wires are connected to different coils, you'll get infinite resistance.

 

[simpsonss]

Hi BrownOut

i'm using a DMM. and then i turn it to 20M ohm, then i measure across two wires it shows 0.00 but with another two it shows 1. is it means that 1 is infinite resistance? if it is true, why for the first try i get 0.00 ohm but not a value? is it the coil for that particular switching is too high?

thank you.

 

[mneary]

A transformer winding may be anywhere from 0.001 to 50 ohms depending on many factors. Very small transformers (and wall warts) primary resistances are even higher.

A reading of 1 (without any zeros) (some meters blink the 1) means infinite. A meter reading of 0.00 ohm is very likely on a secondary winding.

 

[BrownOut]

Use a lower setting on your DMM.