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High voltage DC indicator LED?

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uoficowboy

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Hi - I'm working on designing a board that will have a high voltage DC input. The voltage could be anywhere between 0 and 5KV. I'd like an indicator LED to light up when the voltage is at a dangerous level. Say - 50V. The high voltage is generated on a different board and it is not a strong power supply - so I don't want to put much load on it. The best idea I have is to make a massive voltage divider and run an LED with a comparator. Can anybody think of any better ways of doing it? That approach annoys me as those resistors will have to be a huge value to keep from drawing too much current.

Thanks!
 

karesz

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Hi
I think, these is only way...
You can have a HV resistor at ca 20-25x5x2mm (Vishay), you must it have the 5KV need crepage distances, not only dissipation is volume specifing. Then I would apply guard ring around the attenuated-HV parts...
K.
 

    uoficowboy

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uoficowboy

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karesz said:
Hi
I think, these is only way...
You can have a HV resistor at ca 20-25x5x2mm (Vishay), you must it have the 5KV need crepage distances, not only dissipation is volume specifing. Then I would apply guard ring around the attenuated-HV parts...
K.
Hi Karesz - are you referring to the Vishay HTS series? Those look nice, though they seem to be difficult to get.

Can you tell me what a guard ring is and how you would implement it?

Thanks!

-Michael
 

karesz

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Hali Michi,
No, I did referred to the newer families,FHV100, I saw an article so 2 weeks ago over their & I have to search for that, but yours are good too...
I know as another good HV Resistor deliverer too: Victorin & Metallux_from Metallux i .e.: www.metallux.de/en/products/high-voltage-resistors/high-voltage-divider-series-1000.html _I did used good 10 years ago some similares as yet you can order from Vishay too...
K.
P.s.:
Guarding means: you have to design a GND line (lowest impedance), a ring, around the pins, from (or to) where is some leakage unwished to the rest of your circuit! :)
In your case, dont forget after attenuator a serial resistor + an HVTtransient Transorber to forseen_ if the attenuator R to GNd will be wrong, it has to eliminate/limit the HV/current into your ADC...
 

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