Varistor? Purpose and principle
$begingroup$
In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain the operation principle.
surge-protection varistor
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
$endgroup$
add a comment |
$begingroup$
In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain the operation principle.
surge-protection varistor
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
$endgroup$
2
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
3
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
3
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07
add a comment |
$begingroup$
In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain the operation principle.
surge-protection varistor
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
$endgroup$
In the AL9910 LED driver datasheet it shows a part, which I assume is a varistor, is it so? Varistors are shown to be connected across L and N lines, but here it is connected in series. Please explain the operation principle.
surge-protection varistor
surge-protection varistor
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
asked Mar 24 at 10:19
Roman SimonyanRoman Simonyan
18115
18115
2
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
3
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
3
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07
add a comment |
2
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
3
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
3
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07
2
2
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
3
3
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
3
3
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
This is an NTC current limiting resistor. When plugging in the circuit, the NTC is cold and a bad conductor - this is limiting the charge current to the input capacitor. When the NTC is hot from the power dissipation it will become a good conductor with low losses.
answered Mar 24 at 10:25
jusacajusaca
920319
$endgroup$
add a comment |
$begingroup$
It’s likely a negative temperature coefficient device used to limit inrush current into the bulk storage capacitor and prevent fuses blowing or breakers tripping. It’s quite a common thing to implement.
Once the device warms up its resistance lowers and thus the peak current at initial switch on is significantly reduced.
edited Mar 28 at 23:06
JYelton
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
$endgroup$
add a comment |
$begingroup$
It is a negative temperature coefficient thermistor (NTC). It maintains constant resistance at room temperature. It's resistance will Decreases as temperature rises.
These are commonly used in inrush current limiting to the input capacitors, protects the fuses and breakers from tripping.
Always the most confusing part while referring to these kind of circuits is the symbol, many people represent both (varistor and thermistor) in same way. so we have to decide the device whether it is MOV or NTC based on its operation and application in the circuit (i mean whether it is series, parallel).
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
$endgroup$
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
This is an NTC current limiting resistor. When plugging in the circuit, the NTC is cold and a bad conductor - this is limiting the charge current to the input capacitor. When the NTC is hot from the power dissipation it will become a good conductor with low losses.
answered Mar 24 at 10:25
jusacajusaca
920319
$endgroup$
add a comment |
$begingroup$
This is an NTC current limiting resistor. When plugging in the circuit, the NTC is cold and a bad conductor - this is limiting the charge current to the input capacitor. When the NTC is hot from the power dissipation it will become a good conductor with low losses.
answered Mar 24 at 10:25
jusacajusaca
920319
$endgroup$
add a comment |
$begingroup$
This is an NTC current limiting resistor. When plugging in the circuit, the NTC is cold and a bad conductor - this is limiting the charge current to the input capacitor. When the NTC is hot from the power dissipation it will become a good conductor with low losses.
answered Mar 24 at 10:25
jusacajusaca
920319
$endgroup$
This is an NTC current limiting resistor. When plugging in the circuit, the NTC is cold and a bad conductor - this is limiting the charge current to the input capacitor. When the NTC is hot from the power dissipation it will become a good conductor with low losses.
answered Mar 24 at 10:25
jusacajusaca
920319
answered Mar 24 at 10:25
jusacajusaca
920319
answered Mar 24 at 10:25
jusacajusaca
920319
answered Mar 24 at 10:25
jusacajusaca
920319
920319
add a comment |
add a comment |
$begingroup$
It’s likely a negative temperature coefficient device used to limit inrush current into the bulk storage capacitor and prevent fuses blowing or breakers tripping. It’s quite a common thing to implement.
Once the device warms up its resistance lowers and thus the peak current at initial switch on is significantly reduced.
edited Mar 28 at 23:06
JYelton
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
$endgroup$
add a comment |
$begingroup$
It’s likely a negative temperature coefficient device used to limit inrush current into the bulk storage capacitor and prevent fuses blowing or breakers tripping. It’s quite a common thing to implement.
Once the device warms up its resistance lowers and thus the peak current at initial switch on is significantly reduced.
edited Mar 28 at 23:06
JYelton
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
$endgroup$
add a comment |
$begingroup$
It’s likely a negative temperature coefficient device used to limit inrush current into the bulk storage capacitor and prevent fuses blowing or breakers tripping. It’s quite a common thing to implement.
Once the device warms up its resistance lowers and thus the peak current at initial switch on is significantly reduced.
edited Mar 28 at 23:06
JYelton
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
$endgroup$
It’s likely a negative temperature coefficient device used to limit inrush current into the bulk storage capacitor and prevent fuses blowing or breakers tripping. It’s quite a common thing to implement.
Once the device warms up its resistance lowers and thus the peak current at initial switch on is significantly reduced.
edited Mar 28 at 23:06
JYelton
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
edited Mar 28 at 23:06
JYelton
16.4k2891193
edited Mar 28 at 23:06
JYelton
16.4k2891193
edited Mar 28 at 23:06
JYelton
16.4k2891193
16.4k2891193
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
answered Mar 24 at 10:24
Andy akaAndy aka
244k11184423
244k11184423
add a comment |
add a comment |
$begingroup$
It is a negative temperature coefficient thermistor (NTC). It maintains constant resistance at room temperature. It's resistance will Decreases as temperature rises.
These are commonly used in inrush current limiting to the input capacitors, protects the fuses and breakers from tripping.
Always the most confusing part while referring to these kind of circuits is the symbol, many people represent both (varistor and thermistor) in same way. so we have to decide the device whether it is MOV or NTC based on its operation and application in the circuit (i mean whether it is series, parallel).
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
$endgroup$
add a comment |
$begingroup$
It is a negative temperature coefficient thermistor (NTC). It maintains constant resistance at room temperature. It's resistance will Decreases as temperature rises.
These are commonly used in inrush current limiting to the input capacitors, protects the fuses and breakers from tripping.
Always the most confusing part while referring to these kind of circuits is the symbol, many people represent both (varistor and thermistor) in same way. so we have to decide the device whether it is MOV or NTC based on its operation and application in the circuit (i mean whether it is series, parallel).
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
$endgroup$
add a comment |
$begingroup$
It is a negative temperature coefficient thermistor (NTC). It maintains constant resistance at room temperature. It's resistance will Decreases as temperature rises.
These are commonly used in inrush current limiting to the input capacitors, protects the fuses and breakers from tripping.
Always the most confusing part while referring to these kind of circuits is the symbol, many people represent both (varistor and thermistor) in same way. so we have to decide the device whether it is MOV or NTC based on its operation and application in the circuit (i mean whether it is series, parallel).
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
$endgroup$
It is a negative temperature coefficient thermistor (NTC). It maintains constant resistance at room temperature. It's resistance will Decreases as temperature rises.
These are commonly used in inrush current limiting to the input capacitors, protects the fuses and breakers from tripping.
Always the most confusing part while referring to these kind of circuits is the symbol, many people represent both (varistor and thermistor) in same way. so we have to decide the device whether it is MOV or NTC based on its operation and application in the circuit (i mean whether it is series, parallel).
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
edited Mar 29 at 15:42
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
answered Mar 29 at 1:49
Satish SingupuramSatish Singupuram
1,776317
1,776317
add a comment |
add a comment |
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2
$begingroup$
To limit surge currents thru the diodes, as C1 is charged. As the varistor heats up, its resistance drop. This behavior should greatly increase the lifespan of such systems; the diodes are less stressed.
$endgroup$
– analogsystemsrf
Mar 24 at 10:24
3
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
Mar 24 at 10:35
3
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
Mar 24 at 22:07