Quadratic Equation help?

Thread Starter

Khalid Abur-Rahman

Joined Dec 25, 2008
Can someone show me how to put this equation into quadratic forum?

its specifaclly for JFET design by the way (Common Source Amplifier)

A(v) = -(20k||R(d)/3k-R(d)+350=-4

where k is for kilo ohms..

how do I put it in quadratic form?

Can you show me step by step?


Joined Nov 9, 2007
I am not sure where the -4 comes in, is this the numerical value of the amplifcation?

\(\frac{20000*Rd}{20000+Rd}\) * \(\frac{-1}{3000-Rd+350}\)

If you multiply out the fractions you will get your quadratic in Rd. You should be able to carry on.

Perhaps if you set this equal to -4 you will be able solve for Rd.