04-01-2013, 04:53 PM
RC Phase Shift Oscillator.
[attachment=46551]
Theory:
An oscillator is an electronic circuit for generating an ac signal voltage with a dc supply
as the only input requirement. The frequency of the generated signal is decided by the circuit
elements. An oscillator requires an amplifier, a frequency selective network, and a positive
feedback from the output to the input. The Barkhausen criterion for sustained oscillation is
A_ = 1 where A is the gain of the amplifier and is the feedback factor. The unity gain means
signal is in phase. (If the signal is 180° out of phase, gain will be 1.). If a common emitter
amplifier is used, with a resistive collector load, there is a 180 phase shift between the
voltages at the base and the collector.
EC-I Lab Manual EC-261
BAPATLA ENGINEERING COLLEGE (Autonomous):: BAPATLA
In the figure shown, three sections of phase shift networks are used so that each section
introduces approximately 60_ phase shift at resonant frequency. By analysis, resonant
frequency f can be expressed by the equation,
[attachment=46551]
Theory:
An oscillator is an electronic circuit for generating an ac signal voltage with a dc supply
as the only input requirement. The frequency of the generated signal is decided by the circuit
elements. An oscillator requires an amplifier, a frequency selective network, and a positive
feedback from the output to the input. The Barkhausen criterion for sustained oscillation is
A_ = 1 where A is the gain of the amplifier and is the feedback factor. The unity gain means
signal is in phase. (If the signal is 180° out of phase, gain will be 1.). If a common emitter
amplifier is used, with a resistive collector load, there is a 180 phase shift between the
voltages at the base and the collector.
EC-I Lab Manual EC-261
BAPATLA ENGINEERING COLLEGE (Autonomous):: BAPATLA
In the figure shown, three sections of phase shift networks are used so that each section
introduces approximately 60_ phase shift at resonant frequency. By analysis, resonant
frequency f can be expressed by the equation,