Hello everyone,

Can anyone explain to me what is the angle of impedance ? and like why does this angle exist for capacitive and inductive sensors ?

I ve been searching for the diagram to understand it, but I got lost between all the info there is online !

Many thanks,

 

I have not seen that phrase before but I can guess the following.

Impedance refers to resistance to both DC and AC.
Resistance to DC is called resistance, denoted as R.
Resistance to AC is called reactance, denoted as X and is 90° out of phase with resistance.
Impedance Z is the combination of resistance R and reactance X and is written as

Z = R + j X

where j = √ -1

The resultant phase angle of Z is

θ = atan ( X / R)

using vector analysis.

The reactance XL of an inductor L is

XL = 2 π f L

The reactance Xc of a capacitor C is

Xc = 1 / (2 π f C)

Substitute XL and Xc for the reactance X in the impedance equation given above.

 

Thank you for your explanation.

when I read it, it is written ' loss angle of impedance ' in a book , : “Impedance spectroscopy”, John Wiley & Sons, New York, 1987

But I didn't understand what it means. He speaks about a diagram and angle, but it isn't shown.

"... A real inductivity has losses because of the ohmic resistor of winding, eddy currents in the coil core material and magnetic losses in general. A real capacity has losses caused by limited isolation of the electrodes and dielectric materials. The phase angle between voltage and current is not 90° but decreases minus the loss angle δ. ϕ = ± (90° - δ)"

 

In purely inductive impedance and capacitive impedance there is no resistance. Hence the phase difference between current and voltage is 90°.
When resistance is added, the phase angle becomes less than 90°. When the circuit is purely resistive the phase angle is 0°.

Hence the change in phase angle would be (90 - θ) where θ = atan ( X / R).

 

Now it's clear !

thank you very very much !