Wein Bridge Oscillator Using OP-AMP

1. Define WEIN-BRIDGE OSCILLATOR ?

Ans : The Wien-bridge oscillator is a unique circuit because it generates an oscillatory output signal without having a sinusoidal input source.  Instead, it uses capacitors with initial voltages to create the output.  This circuit can be especially useful if connected to a voltage follower to de-couple the load from the source.

2. ZERO PHASE SHIFT B/W INPUT SIGNAL AND OUTPUT SIGANAL ?

Ans. The amplifier in wein bridge oscillator is of non- inverting type, thereby producing

zero  phase shift between input signals and ouput signals .

3. ADVANTAGES OF WEIN-BRIDGE OSCILLATOR ?

(1) Overall gain is high seems two stage amplifier is used.

(2) The Circuit is a very good sine wave output.

(3)  Frequency stability is good and can be vary over a wide range.

4. DISADVANTAGE OF WEIN-BRIDGE OSCILLATOR ?

(1) Large number of component required to designed 2 stage amplifier.

(2) Very high frequency  can not be generated.

WHAT IS THE PURPOSE OF PHASE SHIFT NETWORK IN A WEIN BRIDGE OSCILLATOR?

ANS;  A Wien bridge oscillator produces sine waves. In order for the sine waves to maintain a steady amplitude, a positive feedback system is used with some sort of control to limit gain. In order for the positive feedback system to work, the waves being "fed back" to the amplifier have to be in phase with the waves being generated. Thus, you need a phase shift network to ensure that the phases of the waves match, which in the case of a positive feedback system means that the generated waves need to go through a 360^o phase shift during the feedback process.