Detecting HV transients

[Paul Burridge]

HI all,

What's the best way to check for the presence on a signal line of high
voltage transients? I can't readily think of an instrument that would
fit the bill. :-|
Talkin' 'bout maybe a couple of thousand (high impedance) volts at
<10ns or thereabouts.

ta,

p
--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[John Larkin]

On Wed, 29 Dec 2004 16:25:38 +0000, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

HI all,

What's the best way to check for the presence on a signal line of high
voltage transients? I can't readily think of an instrument that would
fit the bill. :-|

Digital oscilloscope?

Talkin' 'bout maybe a couple of thousand (high impedance) volts at
10ns or thereabouts.

Such a signal rarely exists on a "signal line". A 10 ns pulse will see
the characteristic impedance of any but a very short line, and its
impedance will be a couple of hundred ohms max. Nature conspires
against fast, high-impedance signals. The practical upshot is that you
don't need a very hi-z probe to detect fast stuff, and it takes a lot
of current to put kilovolts into anything fast.

John

ta,

p

 

Paul Burridge wrote:

HI all,

What's the best way to check for the presence on a signal line of
high
voltage transients? I can't readily think of an instrument that would
fit the bill. :-|
Talkin' 'bout maybe a couple of thousand (high impedance) volts at
10ns or thereabouts.

A neon bulb, NE-2 type, and a 80-100 volt low current supply
(battery?).

Put the bulb across the supply. If the bulb lights up, reduce the
voltage supply until it's just below that point. Place the bulb so
that the glass touches the signal line. Just the glass, no other part
of the bulb circuit.

When the HV pulse comes along it will ionize the neon gas and the
bulb will light and stay lit even after the pulse goes away if the
bulb's supply voltage is set properly.

That way you don't have to sit and watch the thing. If you come
back to it and the light's on, you no a transient happened.

Jim

 

[James Meyer]

On Fri, 31 Dec 2004 05:32:05 GMT, "Marc H.Popek" <LVMarc@worldnet.att.net>
wroth:

non contact em field measurements, rogowski coil or differential B/E dot....

Marco

Or biased neon bulb.

Jim