Capacitor and inductor reactance

[Zeeman2000]

Hello everyone,

I am currently working through a self study book on electronics. I have starting a chapter which is an introduction to Alternating Current. The chapter discusses capacitor and inductor reactance using the following formulas:

XL = 2pifL
XC = 1/2pifC

At the end of the chapter there is a self test which gives a value of a capacitor reactance and the value of a capacitor or inductor and asks to find the frequecy necessary to cause reactance.

The equation for this was not dicussed im the chapter. Can someone explain the equation needed to find the answer?

I tried the equation in reverse which worked for:

100Hz
10H



6.28 * 100 * 10 = 6280 ohms


6280 / 10 / 6.28 = 100Hz


In the self test the values are:



L = 50 μH, XL = 320 ohms, f =


320 / 50 / 6.28 = 1.019108280254777


Book answer was 1.02kHz


Not sure how they are getting this answer. Any help much appreciatted.

 

[Laplace]

Units in the formula are Ohm, Hertz, and Henry. 50 μH = 0.000050 H.

 

[Zeeman2000]

Yes, 50 μH = 0.000050 H

Turns out the question in the book was wrong. I have since checked the errata and it should have read 50mH not 50μH

As even using 0.000050 H gave and answer in MHz

 

[BobK]

Yep, at 50mH the answer in the book is right.

Bob