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# What type of feedback is used in the oscillator circuit?

Top Answer
###### Answered 2010-12-12 07:26:38

There are many different types of oscillator circuits, the majority of which use positive feedback.

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## Related Questions

An amplifier becomes an oscillator when positive feedback is applied. It is the simple way to do it.

The oscillator which is blocked by using transformer is called a blocking oscillator. Generally, the primary is given to the base and secondary is given to the collector of the transistor used in the oscillator circuit.

any circuit which is used to generate an ac voltage without an ac input signal is called an oscillator.

Oscillators are connected externally with the microcontroller to provide high frequency signal to the oscillator circuit in the microcontroller. The oscillator circuit provides the clock signal to the micro controller. Usually "PIEZO CRYSTAL OSCILLATORS" are used in micro controllers.

A local oscillator is used in a superheterodyne radio circuit for example.The incoming radio frequency is mixed with an internal local oscillator circuit to generate a new intermediate frequency (IF) .The local oscillator usually runs at a frequency of 470kHz and is generated by an inductor and capacitor(LC oscillator)

To start the oscillation with the constant amplitude, positive feedback is not the only sufficient condition. Oscillator circuit must satisfy the following two conditions known as Barkhausen conditions:1. The first condition is that the magnitude of the loop gain (A&Icirc;&sup2;) must be unity. This means the product of gain of amplifier 'A' and the gain of feedback network '&Icirc;&sup2;' has to be unity.2. The second condition is that the phase shift around the loop must be 360&Acirc;&deg; or 0&Acirc;&deg;. This means, the phase shift through the amplifier and feedback network has to be 360&Acirc;&deg; or 0&Acirc;&deg;.In practice, to obtain the sustained oscillations at desired frequency of oscillations, oscillator circuit must satisfy some of the basic requirements such as,Circuit must have positive feedbackWhen positive feedback is used in the circuit, the overall circuit gain is given by,

magneto striction oscillator is used to produce ultrasonic waves by using the the principle of inverse piezo electric effect

To isolate the bias circuitry of the transistor from the feedback network with RF currents.

Positive feedback is used in oscillators to keep them running or oscillating. An oscillator is basically an amplifier which has a feedback path from the output back to the input. This permits a portion of the output signal to get back to the input to "keep things going" in stage - to keep things oscillating. The feedback must be positive so that it will "contribute" to the stage being able to keep oscillating. If the feedback was negative, it would serve to damp the oscillation and to "kill" the oscillator.

the types of feedback are positive and negative feedback

negative feedback is used incase of amplifiers.

Resonator is a device used either to generate wave or select specific frequencies from a signal while oscillator is an electronic circuit that creates repetitive signal.

the Colpitts oscillator , named after the inventor of the circuit , is characterised by the use of Two Capacitors in series which are then connected in parallel across the inductor of the resonant circuit for obtaining the required frequency. The junction of the two capacitors is used for the positive feedback used for generating the oscillations. This circuit is used for High frequency oscillators , mainly due to ease of obtaining required ratio of the two capacitor values as per the circuit design. Also the two capacitors in series reduces their total equivalent value , which is not a problem as in HF circuits as the values and size is comparatively low. For information , a corresponding Low frequency circuit is called a Hartley oscillator , also named after its inventor. This uses a tapped inductor &amp; one capacitor for the resonant circuit, since it is more easier to fabricate large value tapped inductors , than to use two bulky ( since the value of capacitors in series is reduced ) capacitors necessary for the equivalent Colpitts oscillator.

amplifier is electronic circuit which is used to increase the amplitude of the input signal without affecting its frequency and phase.

emitter follower is a type of negative feedback ,

Basically an oscillator is a circuit that is used for producing oscillations of current. They are mostly used in radio, to provide a carrier wave for a transmitter, or a local mixing frequency in a superhetrodyne receiver. They are also used at sound frequencies, for musical instruments such as a synthesizer, like a Moog or Korg.

A: actually any active components will oscillate with positive feedback A transistor can be used as an amplifier along with an LC tank circuit to form an oscillator; it is an active device (as LIBURNO states) which will amplify the feedback signal coming out of the LC tank circuit. The tank circuit has a natural resonant frequency, meaning the L and C together will try to generate a specific frequency; this is then fed back into the input of the transistor amplifier, and the output is fed to the LC tank circuit exacerbating this oscillation until it reaches its' maximum level. An inverting amplifier can be used similarly; the output is fed to the input; this will cause the output to change as fast as the amplifier can. The frequency of this design is much harder to control, but potentially higher. Also, without the LC tank, the output voltage will remain lower.

Dc is used to power an oscillator circuit of which the frequency can be controlled such as 60 HZ.

A Wein Bridge Oscillator is a oscillator which is used for the measurement of Audio Frequency.

When a mechanical pressure or load is given to optic axis of the piezoelectric crystal, it develops equal and opposite charges on the mechanical axis of the crystal. This is called piezoelectric effect. Vice versa effect is called inverse piezoelectric effect. This principle is used in piezoelectric oscillator, where a changing voltage across the crystal causes it to change size, which in turn creates a counter voltage which opposes the voltage and creates a feedback ringing effect when used with an amplifier configured as an oscillator. The "ringing" frequency of the oscillation is determined by the mechanical dimensions of the crystal, similar to bells, strings, or pipes. Additionally, depending on the design of the oscillator circuit, capacitors, inductors and resistors may be needed to tune the circuit for optimum start-up and operation.

Crystal Oscillators are more stable oscillator. and used as Local Oscillator in Radio Receivers

A phase-shift oscillator is a simple electronic oscillator circuit. It consists of an inverting amplifier element such as a transistor or op amp, with its output fed back into its input through an filterconsisting of a network of resistors and capacitors. The feddback network 'shifts' the phase of the amplifier output by 180 degrees at the oscillation frequency, to give positive feedback.[1] Phase shift oscillators are mostly used at lower frequencies, often in the audio frequency range as audio oscillators.

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