With the help of circuit diagram explain the working principle of a transistor amplifier as an oscillator.
The circuit diagram for a transistor amplifier as an oscillator is represented as
In an oscillator, a sustained Α.C. output is obtained without any input oscillation. For this to happen, the output of a transistor amplifier is fed back into its input. This is achieved by coupling the winding T1 to winding T2.
When key S1 is closed, the collector current begins to increase, which supports the forward bias of the emitter−base circuit. Collector current increases until it reaches saturation. When the saturation is reached, the magnetic flux linked to winding T1 becomes steady. Hence, the forward bias of the emitter−base circuit is no longer supported. The transistor is now driven into cut-off. This cycle repeats itself and an oscillating output is obtained.