What happens to output if OPAMP its supply is tweaked?LM339: why is the output +5VIssues with OpAmp gain and...
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What happens to output if OPAMP its supply is tweaked?
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What happens to output if OPAMP its supply is tweaked?
LM339: why is the output +5VIssues with OpAmp gain and instrumentation amplifier (Packaged and designed)how to twin-t notch filter topology single supply opampWhy isn't this opamp working correctly?for an audio signal within the rails of an opamp, can its quality be improved by the + and - rail voltages?Supply Voltages for Inverting Amplifierop-amp oscillators weird outputUnexpected opamp outputPA92 OPAMP phase compensationHow can I determine whether this is a “rail to rail” opamp from its datasheet?
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Say the above OPAMP is normally operated with supply of +15V and -15V and output is said to swing from +15V to -15V. But I changed -15V power supply {of OPAMP} to -14V and Vi to:
(a)1V
(b)-15V
(c)1/2V
What should be the output and regions at which the OPAMP operate in each case?
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
op-amp negative-feedback
New contributor
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add a comment |
$begingroup$
Say the above OPAMP is normally operated with supply of +15V and -15V and output is said to swing from +15V to -15V. But I changed -15V power supply {of OPAMP} to -14V and Vi to:
(a)1V
(b)-15V
(c)1/2V
What should be the output and regions at which the OPAMP operate in each case?
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
op-amp negative-feedback
New contributor
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Welcome to EE.SE.
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– Sparky256
2 hours ago
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You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago
add a comment |
$begingroup$
Say the above OPAMP is normally operated with supply of +15V and -15V and output is said to swing from +15V to -15V. But I changed -15V power supply {of OPAMP} to -14V and Vi to:
(a)1V
(b)-15V
(c)1/2V
What should be the output and regions at which the OPAMP operate in each case?
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
op-amp negative-feedback
New contributor
$endgroup$
Say the above OPAMP is normally operated with supply of +15V and -15V and output is said to swing from +15V to -15V. But I changed -15V power supply {of OPAMP} to -14V and Vi to:
(a)1V
(b)-15V
(c)1/2V
What should be the output and regions at which the OPAMP operate in each case?
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
op-amp negative-feedback
op-amp negative-feedback
New contributor
New contributor
edited 2 hours ago
Buzz bee
New contributor
asked 2 hours ago
Buzz beeBuzz bee
62
62
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Welcome to EE.SE.
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– Sparky256
2 hours ago
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You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago
add a comment |
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Welcome to EE.SE.
$endgroup$
– Sparky256
2 hours ago
$begingroup$
You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago
$begingroup$
Welcome to EE.SE.
$endgroup$
– Sparky256
2 hours ago
$begingroup$
Welcome to EE.SE.
$endgroup$
– Sparky256
2 hours ago
$begingroup$
You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago
$begingroup$
You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago
add a comment |
2 Answers
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For an ideal op amp, which has zero input offsets and infinite gain, nothing happens.
For real op amps, the output will change slightly with changes in the power supply voltages. The ratio between the supply changes and the output changes is called the Power Supply Rejection Ratio (PSRR)or Supply Voltage Rejection Ratio (ksvr). The ratio will vary with op amp, and to make things more complicated the number for any op amp will vary with frequency. Higher frequency supply variations will produce a greater output variation than lower frequencies.
In general, for low frequencies, the rejection ratio will be on the order of 80 to 100 dB.
$endgroup$
add a comment |
$begingroup$
Not a thing will happen as long as both power rails are beyond the minimum stated voltage. If the op-amp is not the rail-to-rail output type, then the output voltage is typically Vcc-1.2 volts and Vee + 1.2 volts.
On a more serious note you need to check the minimum load an op-amp will drive. 1 ohm is absurdly low. Even UHF op-amps have a 25 ohm to 50 ohm minimum load. Typical DC and audio op-amps have a 2.2K ohm minimum load. The feedback resistors counts as part of a load, as the (-) input strives to stay at zero volts using this topology.
An all around safe load for full voltage swing is about 10K ohms, with a feedback resistor no less than 10K ohms.
Op-amps vary greatly in output current, so read the almighty datasheet in detail before drawing up a design based on a particular op-amp.
$endgroup$
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
add a comment |
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2 Answers
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$begingroup$
For an ideal op amp, which has zero input offsets and infinite gain, nothing happens.
For real op amps, the output will change slightly with changes in the power supply voltages. The ratio between the supply changes and the output changes is called the Power Supply Rejection Ratio (PSRR)or Supply Voltage Rejection Ratio (ksvr). The ratio will vary with op amp, and to make things more complicated the number for any op amp will vary with frequency. Higher frequency supply variations will produce a greater output variation than lower frequencies.
In general, for low frequencies, the rejection ratio will be on the order of 80 to 100 dB.
$endgroup$
add a comment |
$begingroup$
For an ideal op amp, which has zero input offsets and infinite gain, nothing happens.
For real op amps, the output will change slightly with changes in the power supply voltages. The ratio between the supply changes and the output changes is called the Power Supply Rejection Ratio (PSRR)or Supply Voltage Rejection Ratio (ksvr). The ratio will vary with op amp, and to make things more complicated the number for any op amp will vary with frequency. Higher frequency supply variations will produce a greater output variation than lower frequencies.
In general, for low frequencies, the rejection ratio will be on the order of 80 to 100 dB.
$endgroup$
add a comment |
$begingroup$
For an ideal op amp, which has zero input offsets and infinite gain, nothing happens.
For real op amps, the output will change slightly with changes in the power supply voltages. The ratio between the supply changes and the output changes is called the Power Supply Rejection Ratio (PSRR)or Supply Voltage Rejection Ratio (ksvr). The ratio will vary with op amp, and to make things more complicated the number for any op amp will vary with frequency. Higher frequency supply variations will produce a greater output variation than lower frequencies.
In general, for low frequencies, the rejection ratio will be on the order of 80 to 100 dB.
$endgroup$
For an ideal op amp, which has zero input offsets and infinite gain, nothing happens.
For real op amps, the output will change slightly with changes in the power supply voltages. The ratio between the supply changes and the output changes is called the Power Supply Rejection Ratio (PSRR)or Supply Voltage Rejection Ratio (ksvr). The ratio will vary with op amp, and to make things more complicated the number for any op amp will vary with frequency. Higher frequency supply variations will produce a greater output variation than lower frequencies.
In general, for low frequencies, the rejection ratio will be on the order of 80 to 100 dB.
answered 2 hours ago
WhatRoughBeastWhatRoughBeast
50k22876
50k22876
add a comment |
add a comment |
$begingroup$
Not a thing will happen as long as both power rails are beyond the minimum stated voltage. If the op-amp is not the rail-to-rail output type, then the output voltage is typically Vcc-1.2 volts and Vee + 1.2 volts.
On a more serious note you need to check the minimum load an op-amp will drive. 1 ohm is absurdly low. Even UHF op-amps have a 25 ohm to 50 ohm minimum load. Typical DC and audio op-amps have a 2.2K ohm minimum load. The feedback resistors counts as part of a load, as the (-) input strives to stay at zero volts using this topology.
An all around safe load for full voltage swing is about 10K ohms, with a feedback resistor no less than 10K ohms.
Op-amps vary greatly in output current, so read the almighty datasheet in detail before drawing up a design based on a particular op-amp.
$endgroup$
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
add a comment |
$begingroup$
Not a thing will happen as long as both power rails are beyond the minimum stated voltage. If the op-amp is not the rail-to-rail output type, then the output voltage is typically Vcc-1.2 volts and Vee + 1.2 volts.
On a more serious note you need to check the minimum load an op-amp will drive. 1 ohm is absurdly low. Even UHF op-amps have a 25 ohm to 50 ohm minimum load. Typical DC and audio op-amps have a 2.2K ohm minimum load. The feedback resistors counts as part of a load, as the (-) input strives to stay at zero volts using this topology.
An all around safe load for full voltage swing is about 10K ohms, with a feedback resistor no less than 10K ohms.
Op-amps vary greatly in output current, so read the almighty datasheet in detail before drawing up a design based on a particular op-amp.
$endgroup$
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
add a comment |
$begingroup$
Not a thing will happen as long as both power rails are beyond the minimum stated voltage. If the op-amp is not the rail-to-rail output type, then the output voltage is typically Vcc-1.2 volts and Vee + 1.2 volts.
On a more serious note you need to check the minimum load an op-amp will drive. 1 ohm is absurdly low. Even UHF op-amps have a 25 ohm to 50 ohm minimum load. Typical DC and audio op-amps have a 2.2K ohm minimum load. The feedback resistors counts as part of a load, as the (-) input strives to stay at zero volts using this topology.
An all around safe load for full voltage swing is about 10K ohms, with a feedback resistor no less than 10K ohms.
Op-amps vary greatly in output current, so read the almighty datasheet in detail before drawing up a design based on a particular op-amp.
$endgroup$
Not a thing will happen as long as both power rails are beyond the minimum stated voltage. If the op-amp is not the rail-to-rail output type, then the output voltage is typically Vcc-1.2 volts and Vee + 1.2 volts.
On a more serious note you need to check the minimum load an op-amp will drive. 1 ohm is absurdly low. Even UHF op-amps have a 25 ohm to 50 ohm minimum load. Typical DC and audio op-amps have a 2.2K ohm minimum load. The feedback resistors counts as part of a load, as the (-) input strives to stay at zero volts using this topology.
An all around safe load for full voltage swing is about 10K ohms, with a feedback resistor no less than 10K ohms.
Op-amps vary greatly in output current, so read the almighty datasheet in detail before drawing up a design based on a particular op-amp.
answered 2 hours ago
Sparky256Sparky256
12k21636
12k21636
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
add a comment |
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
Actually in Sergio Franco's book it was written that if we do so we will have to change the reference voltage of the circuit to average of supply and I am a bit confused about it.It is not meant as practical implementation I am just trying to learn.
$endgroup$
– Buzz bee
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
$begingroup$
I have run a OP220 op-amp at +24 and -5 volt, so a perfect balance is not always mandatory.
$endgroup$
– Sparky256
2 hours ago
add a comment |
Buzz bee is a new contributor. Be nice, and check out our Code of Conduct.
Buzz bee is a new contributor. Be nice, and check out our Code of Conduct.
Buzz bee is a new contributor. Be nice, and check out our Code of Conduct.
Buzz bee is a new contributor. Be nice, and check out our Code of Conduct.
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Welcome to EE.SE.
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– Sparky256
2 hours ago
$begingroup$
You can add a better looking schematic using the CircuitLab button on the editor toolbar. Double-click a component to edit its properties. 'R' = rotate, 'H' = horizontal flip. 'V' = vertical flip. Note that when you use the CircuitLab button on the editor toolbar an editable schematic is saved in your post. That makes it easy for us to copy and edit in our answers. You don't need a CircuitLab account, no screengrabs, no image uploads, no background grid.
$endgroup$
– Transistor
48 mins ago