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 yesterday
Roman SimonyanRoman Simonyan
15315
$endgroup$
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 yesterday
Roman SimonyanRoman Simonyan
15315
$endgroup$
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
yesterday
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
yesterday
2
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday
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 yesterday
Roman SimonyanRoman Simonyan
15315
$endgroup$
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 yesterday
Roman SimonyanRoman Simonyan
15315
asked yesterday
Roman SimonyanRoman Simonyan
15315
asked yesterday
Roman SimonyanRoman Simonyan
15315
asked yesterday
Roman SimonyanRoman Simonyan
15315
asked yesterday
Roman SimonyanRoman Simonyan
15315
15315
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
yesterday
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
yesterday
2
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday
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
yesterday
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
yesterday
2
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday
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
yesterday
$begingroup$
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
yesterday
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
yesterday
$begingroup$
But that's definitely not named varistor. Those are overvoltage shunt devices. Nothing to do with what you see in your circuit
$endgroup$
– carloc
yesterday
2
2
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday
add a comment |
2 Answers
2
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 yesterday
jusacajusaca
903318
$endgroup$
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 it’s resistance lowers and thus the peak current at initial switch on is significantly reduced.
answered yesterday
Andy akaAndy aka
243k11184422
$endgroup$
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
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 yesterday
jusacajusaca
903318
$endgroup$
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 yesterday
jusacajusaca
903318
$endgroup$
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 yesterday
jusacajusaca
903318
$endgroup$
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 yesterday
jusacajusaca
903318
answered yesterday
jusacajusaca
903318
answered yesterday
jusacajusaca
903318
answered yesterday
jusacajusaca
903318
903318
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 it’s resistance lowers and thus the peak current at initial switch on is significantly reduced.
answered yesterday
Andy akaAndy aka
243k11184422
$endgroup$
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 it’s resistance lowers and thus the peak current at initial switch on is significantly reduced.
answered yesterday
Andy akaAndy aka
243k11184422
$endgroup$
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 it’s resistance lowers and thus the peak current at initial switch on is significantly reduced.
answered yesterday
Andy akaAndy aka
243k11184422
$endgroup$
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 it’s resistance lowers and thus the peak current at initial switch on is significantly reduced.
answered yesterday
Andy akaAndy aka
243k11184422
answered yesterday
Andy akaAndy aka
243k11184422
answered yesterday
Andy akaAndy aka
243k11184422
answered yesterday
Andy akaAndy aka
243k11184422
243k11184422
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
yesterday
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
yesterday
2
$begingroup$
I believe the source of confusion is that the diagram shows the symbol of an MOV instead of a (NTC) Varistor.
$endgroup$
– Bob S.
yesterday