Page 40 - Semester-IV-Electronics
P. 40

Principle of Oscillator




             Oscillators are active electrical circuits working as a source of


                 alternating voltage or current.


             Audio frequency oscillators used to produce signals of few Hz to 20


                 kHz while radio frequency oscillators used to produce signals of

                 frequencies, few kHz to MHz (104 - 107).



             Oscillators essential components of radio and TV communication

                 systems.



             Oscillators are self-excited active circuits because no external signal is

                 applied in the input circuit.



             In these systems, a conversion of dc energy into ac energy takes place.


             An inductor L and condenser C connected in parallel form a simple


                 oscillatory circuit and such a circuit is called tank circuit.


             If the condenser is charged from a source electrical energy is stored


                 into it.


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