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In a two stage amplifier does the input impedance of the second stage affect the voltage gain of the first stage?
Wiki User
∙ 14y ago
as i understand this impedance is something that impedes, or adds resistance or something like that. ( There are impedance bonds on the railroad to divide the track up into sections for signal purposes) by words, you see the connection with impede and impediment. the impedance, like resistance, would have to be a factor to be reckoned with. I am only familiar with Impedance bonds-they are laid horizontally under the track structure, and are part of the signal system.
Wiki User
∙ 14y ago
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What is voltage follower?
A voltage buffer amplifier is used to transfer a voltage from a first circuit, having a high output impedance level, to a second circuit with a low input impedance level.If the voltage is transferred unchanged (the voltage gain Av is 1), the amplifier is a unity gain buffer; also known as a voltage follower because the output voltage follows or tracks the input voltage. Although the voltage gain of a voltage buffer amplifier may be (approximately) unity, it usually provides considerable current gain and thus power gain
Why FET is an excellent buffer amplifier?
FET is an excellent buffer amplifier because it has an high input impedance by which when we are connecting two networks for transferring out put of one stage to another stage all the power is drown on the second network not on first network.if first stage network has an low input impedance then first circuit drown all power from second circuit.
Difference between transistor and vacuum tube?
They are both used for similar functions, such as oscillators, amplifiers, and switches. The vacuum tube was invented first, and has therefore been around longer than the transistor.
Why you use capacitor in transistor amplifier in output?
The capacitor is used to block DC bias from the output, so that only the AC signal is passed. In an audio amplifier, for instance, unwanted DC in the output would cause distortion when fed to a speaker, or could even damage the speaker or amplifier. In the case of interstage capacitors, they block DC so that the output of the first stage does not affect the bias of the second stage.
What is Lightning impulse withstand voltage?
The instantaneous voltage rating of a given insulation sytem. In the case of a lightning strike, it is very high voltage but only for a split second. The insulation is designed to handle this rated voltage for a split second without damage to the apparatus. Any longer, and damage would result.
What is voltage follower?
A voltage buffer amplifier is used to transfer a voltage from a first circuit, having a high output impedance level, to a second circuit with a low input impedance level.If the voltage is transferred unchanged (the voltage gain Av is 1), the amplifier is a unity gain buffer; also known as a voltage follower because the output voltage follows or tracks the input voltage. Although the voltage gain of a voltage buffer amplifier may be (approximately) unity, it usually provides considerable current gain and thus power gain
Why FET is an excellent buffer amplifier?
FET is an excellent buffer amplifier because it has an high input impedance by which when we are connecting two networks for transferring out put of one stage to another stage all the power is drown on the second network not on first network.if first stage network has an low input impedance then first circuit drown all power from second circuit.
How do you connect a power amp's 70 W output to another amp's rca input?
You can accomplish this through a simple RC network. This network needs to serve several goals: (a) it needs to reduce the source amplifier's output voltage, which depends on this amplifier's design and can be anything from a few volt to 60 or 80 volts peak to peak, to the second amplifier's maximum input voltage (typically in the area of 1 volt peak to peak). (b) it should let work the source amplifier work against a low-impedance sink, because this is what it is designed for. The destination amplifier itself has a very high input impedance. (c) typically, you'd prevent DC coupling by inserting a first-order highpass filter with a -3dB frequency of, say, 20 or 30 Hz.
Difference between transistor and vacuum tube?
They are both used for similar functions, such as oscillators, amplifiers, and switches. The vacuum tube was invented first, and has therefore been around longer than the transistor.
Theory of RC coupled Amplifier?
In a two stage RC coupled amlifier the rransistor are identical and a common power supply is used. the output is provided to the first stage of the amplifier wher it is amplified and this output is uses as a input for the sexound stage this is amplified once again by the other transistor in the sexound stage and the final out put is obtain.
What is second if amplifier?
two hundred
How does an Operational Amp work?
An operational amplifier is an extremely high gain differential voltage amplifier--a device that compares the voltages of two inputs and produces an output voltage that's many times the difference between their voltages. How the operational amplifier performs this subtraction and multiplication process depends on the type of operational amplifier, but in most cases two input voltages control how current is shared between two paths of a parallel circuit. Even a tiny difference between the input voltages produces a large current difference in the two paths--the path that's controlled by the higher voltage input carries a much larger current than the other path. The imbalance in currents between the two paths produces significant voltage differences in their components and these voltage differences are again compared in a second stage of differential voltage amplification. Eventually the differences in currents and voltage become quite large and a final amplifier stage is used to produce either a large positive output voltage or a large negative output voltage, depending on which input has the higher voltage. In a typical application, feedback is used to keep the two input voltages very close to one another, so that the output voltage actually falls in between its two extremes. At that operating point, the operational amplifier is exquisitely sensitive to even the tiniest changes in its input voltages and makes a wonderful amplifier for small electric signals.
How does an operator work?
An operational amplifier is an extremely high gain differential voltage amplifier--a device that compares the voltages of two inputs and produces an output voltage that's many times the difference between their voltages. How the operational amplifier performs this subtraction and multiplication process depends on the type of operational amplifier, but in most cases two input voltages control how current is shared between two paths of a parallel circuit. Even a tiny difference between the input voltages produces a large current difference in the two paths--the path that's controlled by the higher voltage input carries a much larger current than the other path. The imbalance in currents between the two paths produces significant voltage differences in their components and these voltage differences are again compared in a second stage of differential voltage amplification. Eventually the differences in currents and voltage become quite large and a final amplifier stage is used to produce either a large positive output voltage or a large negative output voltage, depending on which input has the higher voltage. In a typical application, feedback is used to keep the two input voltages very close to one another, so that the output voltage actually falls in between its two extremes. At that operating point, the operational amplifier is exquisitely sensitive to even the tiniest changes in its input voltages and makes a wonderful amplifier for small electric signals.
What is the use of buffer circuit?
One prominent application is this: Some circuits have an output impedance very high. If these circuits are coupled with another circuit of low input impedance, the desired functionality of the latter circuit will be drastically affected. Because the first circuit tries to deliver large voltage to the second and the second invariably requires small input voltage. To avoid the circuit disfunctionality, a buffer circuit (a circuit with high i/p impedance and a low o/p impedance) is used. Another application is in the delay matching. This is an advanced topic though. The technology is still new. In delay matching, the latter circuit requires a delay of say "n" seconds after the first circuit's output. A buffer circuit is used in such cases also. The circuit design is totally different than the impedance matching case.
Explain the block diagram of operational amplifier?
It's function is to perform integer and difference solutions to analog inputs. It has - and + inputs. By choosing capacitive or resistive feedback you can alter the signal as needed. <><><> An operational amplifier, often called an op-amp , is a DC-coupled high-gain electronic voltage amplifier with differential inputs and, usually, a single output. Typically the output of the op-amp is controlled either by negative feedback, which largely determines the magnitude of its output voltage gain, or by positive feedback, which facilitates regenerative gain and oscillation. High input impedance at the input terminals and low output impedance are important typical characteristics. Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. External components govern the circuit characteristics. As well as an amplifier designed to respond to a difference in voltage at the two input terminals, another type is designed to respond to different currents at the inputs. This is the Norton op-amp. Modern designs are electronically more rugged than earlier implementations and some can sustain direct short-circuits on their outputs without damage. <><><> An operational amplifier is a voltage amplifier that amplifies the differential voltage between a pair of input nodes. It is a DC-coupled high-gain electronic amplifier with differential inputs and usually a single output. One input is an inverting input and the other input is a non-inverting input. Within limits, the output goes to whatever value is required in order to make the two inputs have the same value. This means there is usually a negative feedback circuit between output and the inverting input. For an ideal operational amplifier, also called an op amp, the amplification gain is infinite.
How does work the op amp?
An op-amp is a phase-inverting voltage amplifier (high input-impedance, low output-impedance) with a large voltage gain. Shunt feedback is connected through an impedance between the output and input terminals. In the simplest configuration there is a shunt feedback resistor - call that R2. If another resistor R1 is conncted in series with the input signal, the op-amp then produces a voltage gain of R2/R1. The new voltage gain is considerably less than the gain without any feedback, and the practical result of this is that the input terminal of the op-amp, which is also the junction of the two resistors, always has an extremely low signal voltage on it and it is termed a 'virtual earth'. The operation of the circuit can be considered by having the signal voltage inducing a signal current equal to Vin/R1 through R1, which then flows through R2 to produce a signal voltage of Vin R2/R1. If the feedback resistor R2 is replaced by a capacitor C, then the gain of the amplifer is the ratio of the capacitor's impedance and the input resistor, R, or Vout/Vin = 1/jwCR. This is know as an 'integrator' because the output voltage is the time integral of the input voltage: it has a phase-lag of 90 degrees and an amplitude that decreases at the rate of 6 dB per octave. If a constant current of i amps is applied to the input terminal, the output voltage rises on a ramp with a slope of i/CR volts per second; and if a variable current is applied, the output voltage is 1/(CR) integral i.dt. This is why an op-ap with a feedback capacitor and a series resistor i known as an analogue integrator.
What is an input reactor?
Just like a line reactor.. A 3-phase Line Reactor is a set of three (3) coils (also known as windings, chokes or inductors) in one assembly. It is a series device, which means it is connected in the supply line such that all line current flows through the reactor, as shown below. Line Reactors are current-limiting devices and oppose rapid changes in current because of their impedance. They hold down any spikes of current and limit any peak currents. This resistance to change is measured in ohms as the Line Reactor's AC impedance (XL) and is calculated as follows: XL = 2 π f L (ohms), where: f = frequency in hertz (cycles per second) harmonic frequency examples: harmonic (60 Hz)frequency (Hz)5th3007th42011th660 L = reactor inductance in henries (H), millihenries (mH) -- H x 10-3, microhenries (µH) -- H x 10-6 By inspection of the XL formula, the Line Reactor is directly proportional to the frequency (f) and the inductance (L). That is, if the impedance of a Line Reactor is 10 ohms at 60 Hz, then at the 5th harmonic (300 Hz) the impedance is 50 ohms. If the inductance (L) is increased, then the impedance will increase proportionally. This increase in Line Reactor impedance will reduce the current in the line. The higher the frequency (Hertz), the lower the current. A Line Reactor's DC resistance (R-ohms) is very low by design so that the power losses (watts-I2R) are low. Line Reactors are rated by % impedance, voltage and current. However, they are sized by % impedance, voltage and motor horsepower. The motor horsepower determines the necessary current rating for the Line Reactor. Line Reactors are rated by impedance, voltage and current. # Impedance (% impedance of load Z) The load impedance (Z) is calculated by this formula: Z = V/I, where Z = load impedance (ohms), V = line voltage (volts), and I = line current (amps) This percent of load impedance also determines the voltage drop across the Line Reactor. For example, a 5% Line Reactor would have a 5% voltage drop. # Voltage rating Since a Line Reactor is a current-sensitive device, the voltage rating is needed for dielectric concerns as a maximum voltage and horsepower. It is also used to determine the current rating when given only voltage and horsepower. # Current rating (amperes) This is the current required by the load(s). It is total current flowing to the load(s) and through the reactor. This current is measured in amperes (amps).
