# A simple question about inductors in AC circuits

#### fankoushat

Joined Mar 8, 2010
17
Hi,

When a pure inductor is connected to an ac source, the voltage taken from the pure inductor is 90 degree leading the current passing through it.

But what is the peak of this voltage signal on the inductor? Does it equal to the peak of the voltage source?

And if we changed this inductor by another pure one, where XL is bigger, will this change the peak of the induced voltage, or only the current signal?

Another question also, what if we insert a pure resistor in this circuit, will the voltage induced on the pure inductor (only) change to lower values? Because R should now decreases all the instantaneous values of the current, so di/dt is lowered at any instant.

Thanks

#### Jony130

Joined Feb 17, 2009
5,162
In steady state UL=Uin because II Kirchhoff's law must hold.
And if we connect resistor in series with inductance then.

$$Vin=\sqrt{V_L^2+V_R^2}$$

And for R=XL -->VR=VL=0.707Vin