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For the successful amplification of the input signal the opamp should have ideally infinite input impedance . It should act like a buffer amplifier
BUFFER amplifier--------------------->
1.input impedance infinity
2.output impedance zero
the reason is that
Any signal source will have source impedance
for the signal not to get lost and dropped across source impedance we ideally insert infinite impedance in series with it which makes the whole drop across the infinite impedance but not across the source
similarly at the output zero impedance is used where in no part of the signal should be left behind in the op amp as a drop
Wiki User
∙ 14y ago
Wiki User
∙ 13y agoHigh input impedance at the input and low output impedance at the output are important typical characteristics of an op-amp.
The reason is "impedance bridging".
Scroll down to related links and look at "Calculation the damping of impedance bridging or power matching an interface connecting Zout and Zin".
Wiki User
∙ 11y agoResistance at the input of a voltage amplifier or a voltmeter is desired to be ideally infinite. This is so that these devices do not become a load for what we input to it. But practically the input resistance of any amplifier ranges from kilo ohms to mega ohms depending on the type and design of the amplifier.
Wiki User
∙ 13y agoAn ideal op amp is said to have infinite input impedance. An actual op amp draws very little current from the input terminal. Impedance = Voltage / Current, so if current is small, then impedance will be very large.
In many applications, an actual op-amp will behave very close to an ideal op-amp, so when designing the circuit, the input impedance is often considered to be infinite.
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Input resistance and output resistance of Voltage series feedback amplifier?
output resistance decreases and input resistance increases
What is voltage shunt amplifier?
In Voltage Shunt Amplifier, the Output voltage is supplied in parallel with the Input voltage through the feedback network.
Why does amplifier gain reduce?
Since we know that the amplifier gain is given by A=Output voltage/input voltage (where A is the amplifier gain) So, it can be written as output voltage=A*input voltage, so when the output part increases gain increases but when input part increases gain decreases
What is voltage gain?
Voltage gain is the ratio of the output voltage of an amplifier to its input voltage.
Input impedance of voltage amplifier?
In audio the input impedance of an amplifier is between 10 kiloohms and 20 kiloohms.
Input resistance and output resistance of Voltage series feedback amplifier?
output resistance decreases and input resistance increases
Ratio or amplifier output signal to its input?
It never referred as ratio but Rather a gain A in the form of output divided by the input and implies voltage A=gain. basically is input resistance divided by the feedback resistance
What is voltage shunt amplifier?
In Voltage Shunt Amplifier, the Output voltage is supplied in parallel with the Input voltage through the feedback network.
Why does amplifier gain reduce?
Since we know that the amplifier gain is given by A=Output voltage/input voltage (where A is the amplifier gain) So, it can be written as output voltage=A*input voltage, so when the output part increases gain increases but when input part increases gain decreases
How a transistor work as an amplifier and as a switch?
"Transistor" name itself revels it transfers resistance from its input to its output (Transfer of resistance). Input resistance varies when input voltage varies, similarly output resistance varies and this leads to voltage variation at the output. Thus input to output voltage variation is called amplification. this is how transistor can be used as an amplifier. If input voltage is minimum output voltage becomes maximum i.e. its output resistance becomes maximum in common emitter configuration. Thus if no voltage is applied at the input its collector resistance becomes infinite or as if open circuit. Similarly if input current is increased output current increases and out put can behave as short circuit. This is how output current can be switched off or on using no input current or with minute input current. Unlike a digital device, the transistor is an analogue device which can be switch on/off to maximum or any gradient in between. Providing a small AC voltage to the base creates an amplified analogue of this signal across the emitter and collector.
What is voltage gain?
Voltage gain is the ratio of the output voltage of an amplifier to its input voltage.
What is voltage offset?
Input offset voltage is the equivalent voltage at the input of an operational amplifier. If an amplifier has a voltage gain of ten and an input offset voltage of 10 microvolts, a level of 100 microvolts will appear at the output with no input. Manufacturers try to design an op amp so the input offset voltage is as small as possible to minimize this error voltage at the output of the amplifier, especially for applications where small voltages are being amplified.
Input impedance of voltage amplifier?
In audio the input impedance of an amplifier is between 10 kiloohms and 20 kiloohms.
What is effect on amplifier output if you increase input impedence?
Impedence is synonymous with resistense. Greater the I, lesser the outputNo.First, it's *resistance* and *impedance*.Now, if the amplifier is a current amplifier, the above makes sense. (higher Zin, less Iin for a constant Vin).But if it's a purely voltage amplifier, it only responds to the input voltage, so the impedance (so long as it's not affecting the source/driving device) will have no effect on a purely voltage-amplifying amplifier.
How do you calculate gain of an inverting and non-inverting OP-Amp configuration?
gain in an op-amp is the output voltage divided by input voltage. for the inverting amplifier , gain(Av)=-(Rf/Ri) ,where Rf => resistance of the feedback path & Ri=> inverting input terminal resistance for the non-inverting amplifier , gain(Av)=(1+(Rf/Ri)) , where Rf => same & Ri=> non inverting input terminal resisance
Why the voltage gain of an FET amplifier is generally less than that obtained using BJT amplifier?
A FET (Field Effect Transistor) is mainly used when the input signal needs to be isolated from the output. A FET has a very high input resistance, so very little current is required from the input. Voltage gain is not the main objective when using a FET.
Amplifier voltage gain is 15db input signal is .8V what is output voltage?
54.6dB
