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Why voltage gain is high in op amp?
A practical opamp is designed to approach the characteristics of the ideal opamp as closely as possible. The open loop voltage gain of an ideal opamp is infinite, so while this is actually impossible to achieve practical opamps are built with as high an open loop voltage gain as possible.
Why do you use a delayed AGC?
The disadvantage of automatic gain control, attenuating even the weak signal, is overcome by the use of delayed automatic gain control (dagc).
High frequency response of RC coupled amplifier?
At high frequency the capacitor coupling the stages has low reactance, therefore the net resistance of that stage is not equal to next stage, due to this poor impedance matching the power of this stage is not transferred fully to next stage and hence gain falls. And also at high frequency transistor capacitance comes into existence which provides feedback and it thus lowers gain.
What is the effect of bypass capacitor on frequency response?
Gain in a CE configuration of a BJT is collector resistance divided by emitter resistance, subject to the limit of hFe. The emitter bypass capacitor will have lower impedance at high frequency, so the gain will be higher at higher frequency, making this a high-pass amplifier.
What are the applications of Class B Power Amplifier?
Its used in collector amplitude modulation,Radio frequency recievers ..etc
Why voltage gain is high in op amp?
A practical opamp is designed to approach the characteristics of the ideal opamp as closely as possible. The open loop voltage gain of an ideal opamp is infinite, so while this is actually impossible to achieve practical opamps are built with as high an open loop voltage gain as possible.
Why output impedence is high in opamp?
Output impedance in an op-amp is not high - it is low - input impendance is high, and this is because the input stage transistors have high gain.
Frequency response curve of RC coupled amplifier?
at low frequency less than 50hz the voltage gain decreases with decreasing frequency and at mid frequency{50hz to 20khz} the voltage gain is uniform because resistor value are independent of frequency change and at the high frequency votage gain falls.
Why gain is fall at high frequency in r-c coupled amplifier?
The gain of an r-c coupled amplifier falls at high frequency because the capacitive reactance of the capacitor tends to zero.
How do you achieve a wide bandwidth and a high voltage gain in an amplifier?
Do you mean with opamp circuits or tuned RF/IF amplifiers? In both cases several stages can be used to increase the gain. With opamp circuits though getting both wide bandwidth and high gain at the same time is difficult. With tuned RF/IF amplifiers two things can be done to get wide bandwidth: 1) reduce the Q of the tuned coupling transformers connecting the stages and 2) stagger the tuning of the tuned coupling transformers connecting the stages so that some are detuned high while others are detuned low.
Why it is desirable for an op amp to have a high CMRR?
A high CMRR prevents the opamp from passing undesirable common mode signals.
Why do you use a delayed AGC?
The disadvantage of automatic gain control, attenuating even the weak signal, is overcome by the use of delayed automatic gain control (dagc).
High frequency response of RC coupled amplifier?
At high frequency the capacitor coupling the stages has low reactance, therefore the net resistance of that stage is not equal to next stage, due to this poor impedance matching the power of this stage is not transferred fully to next stage and hence gain falls. And also at high frequency transistor capacitance comes into existence which provides feedback and it thus lowers gain.
What is the effect on voltage gain in a common emitter amplifier when the decoupling capacitor is removed?
The emitter bypass capacitor, in a typical common emitter configuration, increases gain as a function of frequency, making a high pass filter. Removing the capacitor will remove the gain component due to frequency, and the amplifier will degrade to its DC characteristics.
What is an Op amp Circuit?
op-amp rolloff is an inherent low pass filter built into op-amp chips. Because op-amps have such a high gain, they are prone to breaking into high-frequency oscillation; therefore limiting the gain by frequency with a built in low pass filter helps stop this from happening. Imagine a super small signal is leaking into an op amp, because of the high gain it becomes no longer negligible and we have a high frequency signal when the output should be zero. The low pass filter lowers the gain at these High frequencies. Now, this will naturally create gain limits when designing circuits, forcing an upper bandwidth. This is adjusted for by lowering the gain you design into your circuit for the bandwidth you are dealing with (which is one of many reasons we build multi-stage amplifiers)
What is rolloff in an op-amp circuit?
op-amp rolloff is an inherent low pass filter built into op-amp chips. Because op-amps have such a high gain, they are prone to breaking into high-frequency oscillation; therefore limiting the gain by frequency with a built in low pass filter helps stop this from happening. Imagine a super small signal is leaking into an op amp, because of the high gain it becomes no longer negligible and we have a high frequency signal when the output should be zero. The low pass filter lowers the gain at these High frequencies. Now, this will naturally create gain limits when designing circuits, forcing an upper bandwidth. This is adjusted for by lowering the gain you design into your circuit for the bandwidth you are dealing with (which is one of many reasons we build multi-stage amplifiers)
What are the advantages of wien bridge oscillator?
RC phase shift oscillator is used to generate frequency in audio range and it is a fixed audio frequency oscillator where as wien bridge oscillator is a variable audio frequency oscillator for high frequency oscillations it is better to design wide band amplifier with LC network
