Editing Wien bridge oscillator (section)

===Frequency determining network===

{{unreferenced section|date=September 2015}}

:<math> H(s) = \frac { R_1 / (1 + sC_1 R_1)  } {R_1 / (1 + sC_1 R_1) + R_2 + 1/(sC_2)} </math>

:<math> H(s) = \frac { s C_2 R_1 } {(1 + s C_1 R_1) (s C_2 R_1  / (1 + sC_1 R_1) + s C_2 R_2 + 1 )} </math>

:<math> H(s) = \frac { s C_2 R_1 } {s C_2 R_1 + (1 + s C_1 R_1) (s C_2 R_2 + 1 )} </math>

:<math> H(s) = \frac { s C_2 R_1 } {C_1 C_2 R_1 R_2 s^2 + (C_2 R_1 + C_2 R_2 + C_1 R_1) s + 1 } </math>

Let R=R<sub>1</sub>=R<sub>2</sub> and C=C<sub>1</sub>=C<sub>2</sub>

:<math> H(s) = \frac { s C R } {C^2 R^2 s^2 + 3 C R s + 1 } </math>

Normalize to ''CR''=1.

:<math> H(s) = \frac { s } {s^2 + 3 s + 1 } </math>

Thus the frequency determining network has a zero at 0 and poles at <math>-1.5\plusmn \frac{\sqrt{5}}{2}</math> or −2.6180 and −0.38197.