Essentials of Transistor Oscillator

Fig. below shows the block diagram of an oscillator. Its essential components are:

1. Tank Circuit: It consists of inductance coil(L) connected in parallel with capacitor(C ). The frequency of oscillations in the circuit depends upon the values of inductance of the coil and capacitance of the capacitor.
2. Transistor Amplifier: The transistor amplifier receives d.c. power from the battery and changes it into a.c. power for supplying to the tank circuit. The oscillations occurring in the tank circuit are applied to the input the transistor amplifer. The output of the transistor can be supplied to the tank circuit to meet the losses.
3. Feedback circuit: The feedback circuit supplies a part of collector energy to the tank circuit in correct phase to aid the oscillations. ie. provides positive  feedback.

Types of Transistor Oscillators

1. Hartley Oscillator
2. Colpitt’s Oscillator
3. Phase Shift Oscillator
4. Tuned Collector Oscillator
5. Wein Bridge Oscillator
6. Crystal Oscillator