# Maths Of Gyrator And Bandaxall

#### Jony130

Joined Feb 17, 2009
4,928

#### Jony130

Joined Feb 17, 2009
4,928
What do you think it should be?
Hmm,
$Zin=\frac{R_L*(R*R_L*C^2*\omega^2+1)}{1+ \omega^2*R_L^2*C^2} + \frac{ j\omega*R_L*C(R-R_L)}{1+ \omega^2*R_L^2*C^2 }$

#### The Electrician

Joined Oct 9, 2007
2,724
Hmm,
$Zin=\frac{R_L*(R*R_L*C^2*\omega^2+1)}{1+ \omega^2*R_L^2*C^2} + \frac{ j\omega*R_L*C(R-R_L)}{1+ \omega^2*R_L^2*C^2 }$
What's wrong with the expression on the Wikipedia site?

They have:

$Zin=(R_L+j\omega*R_L*R*C)||(R+\frac{1}{j\omega*C})$

If you expand their expression and then rationalize, don't you get exactly the same as your expression?

#### metricaez

Joined Sep 22, 2009
3
Hi!
I need the analysis and the formula for exactly those 2 circuits. The information you granted me had similar circuits but not the same (except for the bandaxall fourth link wich refers to the circuit I need). I know the gyrator circuit apears on Audio Radio Handbook by National Semiconductor. I would buy the book but it isnt sold here in Uruguay and as I m under 18 i dont have a credit card to buy it online.
If someone could scan the chapters of the book refered to that filter or/and analyse it I would be really thankfull.
Thanks again for the suport and forgive my English as I m a Spanish speaker.

PS: If you scan the book please send it to metricaez@hotmail.com