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It will oscillate if the loop gain exceeds 1 when the phase difference round the loop is 360 degrees. The frequency of oscillation is set by the loop phase being equal to 360 degrees.
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Why negative feedback amplifier is preferred to positive feedback amplifier?
The negative feedback tends to stabilize the circuit; positive feedback would make it more unstable. For example, the "beta" of a transistor OF THE SAME SERIES - this is basically the amplification factor - may vary between 100 and 1000. With negative feedback, the circuit is hardly affected by these changes in beta - at the cost of a reduced amplification.
What is a programmable gain amplifier?
A programmable gain amplifier (PGA) is a electrical circuit that allows the controller (user, machine) to adjust its transfer function so as to provide larger or lesser voltage gain. Usually it is a simple circuit, using an operational amplifier with negative feedback. In the negative feedback loop, several resistors and switches open and close, in order to achieve the desirable gain.
What is current feedback shunt?
The effect of current shunt feedback in an amplifier is to The effect of current shunt feedback in an amplifier is to
What is Op-Amp non inverting amplifier?
When the feedback of the output terminal of an Op-Amp is given to the non-inverting terminal [pin 3 for IC-741] of that Op-Amp , then , that circuit is called non-inverting amplifier using Op-Amp. This circuit is called non-inverting because the output signal of this circuit is in phase with the input signal.
Design and implementation of a buffer circuit using operational amplifier?
design and implementation of a buffer circuit using operational amplifier
Why negative feedback amplifier is preferred to positive feedback amplifier?
The negative feedback tends to stabilize the circuit; positive feedback would make it more unstable. For example, the "beta" of a transistor OF THE SAME SERIES - this is basically the amplification factor - may vary between 100 and 1000. With negative feedback, the circuit is hardly affected by these changes in beta - at the cost of a reduced amplification.
Why op amp circuit without negative feedback so unstable?
I f an amplifier has a great gain lets say 1000 and the power supply is 10 v then 10 mv will saturate the amplifier to either rail some amps has 10mv just in offset voltage
What is a programmable gain amplifier?
A programmable gain amplifier (PGA) is a electrical circuit that allows the controller (user, machine) to adjust its transfer function so as to provide larger or lesser voltage gain. Usually it is a simple circuit, using an operational amplifier with negative feedback. In the negative feedback loop, several resistors and switches open and close, in order to achieve the desirable gain.
Why is negative feedback used in high gain amplifier?
A: Well for one thing if it is positive feedback the amplifier will saturate to one one side of the power buss or the other. An operational amplifier open loop gain can be 90Db which a tremendous gain so some negative feedback is necessary to reduce the gain and make the amplifier behave in the linear region for amplification
What does feedback do?
The purpose of negative feedback in electronic amplifier circuits is to make the performance of the circuit depend as far as possible on well defined passive components like resistors and fixed capacitors, and not on the active devices which have a less well defined performance.
What is current feedback shunt?
The effect of current shunt feedback in an amplifier is to The effect of current shunt feedback in an amplifier is to
What negative feedback in a circuit?
A part of output which is provided again ti theinput but with some phase difference is called negative feedback. i hope u get it..
Why feedback amplifier is used?
transitors amplify signals in a very non-linear fashion. somehow (i don't know how), adding in the negative output of the transistor (negative feedback loop) makes the output much more linearmostly for stabilization, but there can be other reasons in specific cases.
How op amp works as oscillator?
oscillator needs positive feedback in order to produce the undamped oscillations .This is done with help of he amplifier circuit.The oscillations are produced by the tank circuit cosisting of inductor and capacitor.The output of this tank circuit is fedback to the transistor which amplifies it and give back to the tank circuit input.If the gain of the circuit consisting of tank circuit and amplifier is more than one and the feedback given to tank circuit is in phase then we get undamped scillations as the output.
What is effect of an unbypassed resistor on the common emitter amplifier circuit?
An emitter resistor in a common emitter circuit will cause the stage to experience the effects of degenerative feedback if it is unbypassed. The degenerative feedback reduces gain. This is probably the primary effect in the described circuit.
How can an amplifier become an oscillator?
An amplifier can become and oscillator by adding positive feedback from the output back to the input. Positive feedback means that the phase of the signal fed back to the input is the same as the phase of the output signal. In the case of a high frequency oscillator, a tuned circuit (inductor and capacitor) or a quartz crystal in the input circuit will determine the frequency of oscillation.
What is feedback circuit?
A circuit in which output feeding back to input to increase or decrease the gain is called feedback circuit. Basically part of output feeding to input in such way that it increase the value of input is positive feedback and it also increase gain of circuit and similarly to it when part of output feeding to input in such way that it decrease the value of input is called negative feedback it also decrease the gain of circuit.
