How transistor can be used as an oscillator?

A transistor can be operated as an oscillator for producing continuous undamped oscillations of any desired frequency if tank (or oscillatory) and feedback circuits are property connected to it. All oscillators under different names have similar function i.e. they generate continuous undamped output.

When might a voltage controlled oscillator be needed?

To generate FM, a voltage controlled oscillator is needed to enable the instantaneous frequency of the carrier to be varied by the baseband signal. This usually employs a varactor diode or a transistor reactance circuit to provide a voltage controlled capacitance (Coates, 1975).

What type of arrangement is required to sustain the oscillations of the oscillator circuit?

For an RC oscillator to sustain its oscillations indefinitely, sufficient feedback of the correct phase, that is positive (in-phase) Feedback must be provided along with the voltage gain of the single transistor amplifier being used to inject adequate loop gain into the closed-loop circuit in order to maintain …

How do you control the frequency of an oscillator?

By varying the total impedance of each oscillator oscillatory network, frequencies of oscillations are controlled using potentiometers. The main advantage of the proposed circuits is that both the amplitude and frequency of the waveforms generated can be independently controlled.

How BJT is used in oscillator?

BJT oscillators work on the principle of electrical resonance in a circuit. Feedback network is a network which sends back part of output power to the input and helps in creating oscillations in the output for a DC input. This is known as positive feedback as the feedback power is added to the input power.

What is the principle of oscillator?

There are many types of electronic oscillators, but they all operate according to the same basic principle: an oscillator always employs a sensitive amplifier whose output is fed back to the input in phase. Thus, the signal regenerates and sustains itself. This is known as positive feedback.

What is the importance of voltage controlled oscillator in FSK transmitters and receivers?

With this arrangement, when an oscillation signal is selectively output in a high or low frequency band by switching the LC resonator circuit, the voltage controlled oscillator can increase the difference between the rates of change in the high and low frequency bands.