# Hartley Oscillator

Transistorised Hartley Oscillator The amplifier stage uses an active device as a transistor in common emitter configuration. The practical circuit is shown in the figure. The resistance R1 and R2 are biasing resistances. The RFC is the radio frequency choke. Its reactance value is very high for high frequencies, hence it can be treated as … Continue reading Hartley Oscillator

# Tuned Oscillator Circuits

The oscillators which use the elements L and C to produce the oscillations are called LC oscillator or tuned oscillator. The circuit using elements L and C is called tank circuit or oscillatory circuit, which is an important part of LC oscillators. This circuit is also referred as resonating circuit, or tuned circuit. These oscillators … Continue reading Tuned Oscillator Circuits

# Wiens Bridge Oscillator

Generally in an oscillator, amplifier stage introduces 180° phase shift and feedback network introduces additional 180° phase shift, to obtain a phase shift of 360° around a loop. This is required condition for any oscillator. But wiens bridge oscillator uses a non inverting amplifier and hence does not provide any phase shift during amplifier stage. As total phase … Continue reading Wiens Bridge Oscillator

# Classification of Oscillators

The oscillators are classified based on the nature of the output waveforms, the parameters used, the range of frequency etc. The various ways in which oscillators are classified as : Based on the Output Waveform Under this, the oscillators are classified as sinusoidal and non sinusoidal oscillators. The sinusoidal oscillator generate purely sinusoidal waveform at … Continue reading Classification of Oscillators

# Barkhausen Criterion

Consider basic inverting amplifier with an open loop gain A. The feedback network attenuation factor β is less than unity. As basic amplifier is inverting, it produces a phase shift of 180° between input and output as shown in the figure. Now the input Vi applied to the amplifier is to be derived from its output Vo using feedback … Continue reading Barkhausen Criterion

# RC Phase Shift Oscillator

RC Phase Shift Oscillator basically consists of an amplifier and a feedback network consisting of resistors and capacitors arranged in ladder fashion. Hence such an oscillator is also called ladder type RC Phase Shift Oscillator. To understand the operation of this oscillator let us study RC circuit first, which is used in the feedback network … Continue reading RC Phase Shift Oscillator