An electronic device that generates sinusoidal oscillations of desired frequency is known as a sinusoidal oscillator. Oscillator does not create energy, but merely acts as an energy converter. It receives DC energy and changes it into AC energy of desired frequency. The frequency of oscillations depends upon the constants of the device. Although an alternator produces sinusoidal oscillations of 50Hz, it cannot be called an oscillator. Firstly, an alternator is a mechanical device having rotating parts whereas an oscillator is a non-rotating electronic device. Secondly, an alternator converts mechanical energy into AC energy while an oscillator converts DC energy into AC energy. Thirdly, an alternator cannot produce high frequency oscillations whereas an oscillator can produce oscillations ranging from a few Hz to several MHz.
Advantages - Although oscillations can be produced by mechanical devices (e.g. alternators), but electronic oscillators have the following advantages:
- An oscillator is a non-rotating device. Consequently, there is little wear and tear and hence longer life.
- Due to the absence of moving parts, the operation of an oscillator is quite silent.
- An oscillator can produce waves from small (20 Hz) to extremely high frequencies (> 100 MHz).
- The frequency of oscillations can be easily changed when desired.
- It has good frequency stability i.e. frequency once set remains constant for a considerable period of time.
- It has very high efficiency