Wien Bridge Oscillator Frequency Calculator

How it is calculated

The tool assumes the standard Wien bridge with equal resistors and equal capacitors in both arms. Resistance R is entered in kΩ and capacitance C in nF, then converted to ohms (× 1,000) and farads (× 10⁻⁹). The frequency is f = 1 ÷ (2π·R·C). It also shows the angular frequency ω = 2π·f, which equals 1 ÷ (R·C), in rad/s and the period T = 1 ÷ f in milliseconds. Values of 1,000 Hz or more are displayed in kHz. Both inputs must be above zero. The result is the ideal frequency from the component values; it does not check amplifier gain, which the circuit needs for oscillation to start and hold, nor component tolerance.

Common mistakes

• Entering R in ohms or C in microfarads. The fields are kΩ and nF, so 10,000 for a 10 kΩ resistor would give a frequency 1,000 times too low.
• Mixing different R or C values in the two arms. The formula assumes they are equal; with unequal parts the real frequency is different from this result.
• Expecting the calculated frequency to appear on the scope exactly. Resistor and capacitor tolerances of 5 or 10 percent move it by a similar amount.
• Forgetting that the oscillator needs enough amplifier gain. The frequency is only half of the design, since too little gain gives no oscillation.
• Confusing ω in rad/s with f in Hz. They differ by the factor of 2π, so use f when tuning a signal generator.