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What is Barkhausen criteria for oscillation?
Looking at the expression, we note that when AB = -1, the gain is infinite this represents the condition for oscillation The requirements for oscillation are described by the Barkhausen criterion: The magnitude of the loop gain AB must be 1 The phase shift of the loop gain AB must be 180,or 180 plus an integer multiple of 360. It should be mentioned that the criterion is necessary but not sufficient. The criterion is just an observation based on the assumption of a linear circuit.
What should be the phase margin and gain margin For stability?
A very high gain margin or phase margin produces stable feedback systems, however they may be sluggish in operation. If the gain margin is close to unity of the phase margin is close to zero, the system will be highly oscillatory and produce overshoots with large amplitudes that take a while to settle. Having a gain of 6 dB or phase margin of 30 - 35 degrees will give you a relatively stable system. However there exists cases where this may not be so. :-)
Why only low frequencies are used in hartley oscillators?
an Hartley oscillator uses a tapped inductor ( i.e an inductor with an additional connection at a suitable position in turns of the coil. ) with a specific tap ratio as per the circuit gain and design. For Low Frequency oscillators large inductances are required which have large number of coil turns. It is possible to get suitable ratios for such values hence this circuit is prefered.
What is the working principle of a colpitts oscilator?
The principle of LC tank ckt. which produces 180 deg phase shift the loop gain AB=1 in hartley oscillator are used 2 inductors and 1 capacitor.
What is the RMS volts formula for 3 phase system?
In three-phase systems, we always consider individualline or phase currents, or individual line or phase voltages. In other words, we treat currents and voltages no differently from single-phase currents or voltages (i.e. we don't 'combine' them because they are three-phase quantities). So these quantities are expressed in r.m.s. values.
Closed loop gain for feedback oscillators?
Feedback oscillators have a closed loop gain of
Feedback oscillators have a closed loop gain of?
unity
How phase shift oscillator introduces phase shaft of 180 degree?
You mean "how does a phase shift oscillator introduce a phase shift of 180 degrees?" OK, we need two things for this type of oscillator: 1. A loop gain of more than 1.0, 2. A loop phase shift of zero degrees. The PSO achieves the gain using a valve, transistor, or op amp. It achieves the loop phase shift using (i) an inverting amplifier, equal to a phase shift of 180º, plus (ii) a network (usually resistor-capacitor) with a further phase shift of 180º. The loop shift is thus (180+180) = 360º/ zero degrees. It's easiest to use a three-part phase shift network, as the theoretically-possible two-part is difficult to make work, and the four-part is unneccessarily complex. The required phase shift of exactly 180º occurs at only one frequency, determined by the values of R and C.
What are the advantages and disadvantages in using common collector amplifier?
Current gain. At the cost of no voltage gain.
Why do you get a inverted waveform when a AC signal is passed to a amplifier?
Due to its negative gain and 180' phase shift between base and collector
What is the implication of negative voltage gain?
If the input and output are expressed in volts, then negative gain means a 180° phase shift. If the ratio of output to input is expressed in dB, then negative gain means attenuation, i.e., less power out than power in.
How complex numbers are used in determining gain of a system?
Since complex numbers can be expressed as magnitude and angle, a plot of a system's response can be approximated with a Bode plot (see related link). The gain is the magnitude, and the phase shift is the angle change of the system.
What is the various condition of a general oscillator?
The condition is called Barkausen criteria.They are 1. The loop gain of the circuit should be unity. 2. The total phase shift around the circuit should be zero.
What is the purpose of a phase-shift network in a Wien bridge oscillator?
A Wien bridge oscillator produces sine waves. In order for the sine waves to maintain a steady amplitude, a positive feedback system is used with some sort of control to limit gain. In order for the positive feedback system to work, the waves being "fed back" to the amplifier have to be in phase with the waves being generated. Thus, you need a phase shift network to ensure that the phases of the waves match, which in the case of a positive feedback system means that the generated waves need to go through a 360o phase shift during the feedback process.
What is mean by stability of the oscillator?
Stability of the oscillator means the how much frequency stability it have. Measure of frequency stability comes from "rate of change of phase w.r.t frequency", the more it is the more stable the oscillator is, because we know that one condition for oscillation is that the loop gain phase shift should be zero, hence if due to ckt. parameters there is some change in phase then by very little variations in frequency we can bring back the loop gain phase shift to zero. ex. is LC tank circuit which act as an osciilator at resonant frequency. Frequency stability can also be measure from quality factor, the higher it is the more stable ckt. is,Parikshit ParasherB-tech ECE, PG power engg.parikshit_parasher@yahoo.co.in
Can anyone shape shift?
No One can shape shift IRL. Unless you count weight loss/weight gain.
What is Barkhausen criteria for oscillation?
Looking at the expression, we note that when AB = -1, the gain is infinite this represents the condition for oscillation The requirements for oscillation are described by the Barkhausen criterion: The magnitude of the loop gain AB must be 1 The phase shift of the loop gain AB must be 180,or 180 plus an integer multiple of 360. It should be mentioned that the criterion is necessary but not sufficient. The criterion is just an observation based on the assumption of a linear circuit.
