The basic configuration using a transistor is shown in figure bellow. This circuit produces a sine wave low frequency signal in the frequency range between some hertz and some hundreds quilohertz. In the practical applications is recommended make C1 = C2 and R1 = R2.

**Formula 1 **

Frequency:

**Where: **

f is the frequency in hertz (Hz)

R1 and R2 are the resistances in ohm (Ω)

C1 and C2 are the capacitances in farads (F)

π is the constant 3.1415

**Application example: **

Calculate the frequency of a Wien-Bridge Oscillator where C1 = C2 = 20 nF and R1 = R2 = 20 kΩ.

**Data: **

R1 = R2 = 20 kΩ

C1 = C2 = 20 nF

**Using formula 1:**

f = 1 592.35 Hz or 1.592 kHz