Q. Explain the measurement of frequency in detail by using Wein's bridge.

Sol. The Wein's bridge is presented here not only for its use as an AC bridge to measure frequency but also for its application in various other useful circuits.

We find, for example a Wein's bridge in the harmonic distortion analyzer, where it is used as a notch filter, discriminating against one specific frequency.

The Wein's bridge has a series of RC combination in the adjoining arm.

It most Wein's bridge circuits, the components are chosen such that. This reduces equation for the frequency of the bridge. In a practical bridge, capacitors C₁ and C₃ are fixed capacitors and resistors R₁ and R₃ are variable resistors controlled by a common shaft. Provided now that the bridge may be used as a frequency determining devices, balanced by a single control. This control may be calibrated directly in terms of frequency.

] Because of its frequency sensitivity, the Wein's bridge may be difficult to balance (unless the waveform of the applied voltage is purely sinusoidal), since the bridge is not balanced for any harmonics present in the applied voltage, these harmonics will sometimes produce an output voltage masking the true balance point.