Question

Mark for review
33 When the oscillator acts as amplifier and
what is the gain in it?

Answer 1

The gain in the oscillator when it acts amplifier is    $A_{f} =\frac{A}{(1-AB)}$

• The oscillator acts as an amplifier with positive feedback. The gain of the amplifier having  positive feedback is given by relation

                          $A_{f} =\frac{A}{(1-AB)}$

• If AB=1, then the value becomes infinite then the amplifier is capable in producing output eventhough no input is given. We can also say that the oscillations occur.
• Therefore an amplifier becomes an oscillator when the feedback gain of the amplifier is 1/A.
• This condition is called as Barkhausen‘s criteria for the oscillations.