Inductance ratio

Thread Starter

debjit625

Joined Apr 17, 2010
790
Isnt it a error at http://www.allaboutcircuits.com/vol_2/chpt_9/7.html

Here the Inductance ratio is given as (N secondary/N primary)^2 which should be (Number of primary turns / Number of secondary turns)^2

Now in example, for a step up transformer 125V to 250V is given

This concurs with our example of the 2:1 step-up transformer....
And how this ratio could be 2:1 it should be 1:2 as per Primary:Secondary .

EDIT :: here is another thing
The transformation ratio of impedance is the square of the voltage/current transformation ratio, the same as the winding inductance ratio:
Should both be same?
 
Last edited:

Thread Starter

debjit625

Joined Apr 17, 2010
790
How a step up transformer which step up 125V to 250V have 2:1 ratio rather 1:2, as it should have low primary turns w.r.t secondary turns.
 

studiot

Joined Nov 9, 2007
4,998
Remember

Turns ratio = voltage ratio = 1/current ratio = N2/N1

Where N2 is the secondary turns N1 is the primary turns.

Thus there are twice as many secondary turns as primary to step up 125 volts primary to 250 volts secondary.
Thus the turns ratio = 2/1 = 2:1

Of course the current ratio is the reciprocal ie 1/2 = 1:2 and the secondary current is half the primary.
 
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