Surge protector question

[rainman1]

I've seen in a lights protector the next circuit.
The PTC was very close to the MOV then its seen here.
I dont understand what the PTC's duty?
I mean when a light comes, 1000V can be applied there and it will burn the PTC, so whats the point?

Thanks.

 

[rainman1]

What i dont understand is that if there is a lightning, then until the PTC will get burned, the ROV willl short the load and therefore will cause the electric power in the house to fall down.
So whats the PTC's job here?

 

[Willbe]

I dont understand what the PTC's duty?
I mean when a light comes, 1000V can be applied there and it will burn the PTC, so whats the point?

In principle,
high voltage causes high current in the MOV. High current in this series circuit causes heating in the PTC so it goes to a high resistance state, thus limiting the current.

 

[rainman1]

In principle,
high voltage causes high current in the MOV. High current in this series circuit causes heating in the PTC so it goes to a high resistance state, thus limiting the current.

But the light causes such a big voltage that the PTC is burned, no?

 

[rainman1]

help please

 

[Willbe]

You mean lightning?
Reliable lightning protection requires a more sophisticated circuit, or components capable of absorbing enormous energy. To some extent power lines soften the requirements for surge protectors, though.