Lightning

[Tim Ressel]

Well, its like this: Lightning is *caused* by a static potential difference
between the clouds and the ground (or cloud to cloud). The initial strike is
definitely DC, and FYI the typical dicharge is rekoned to be 100,000 volts at
100,000 amps!!!  The larger strikes usually have multiple dicharges as nearby
cloud discharge their energy into the newly depleted cloud. Secondary ringing is
a likelyhood as many resonators get one heck of an impulse to set them to
ringing, both electrically and acoustically.

How do I know about lightning? One of my tasks is testing Radiated Immunity, and
one source of EMI waves is nearby lightning strikes. I have measured hundreds of
volts on short pieces of cable during a strike! Let this be a warning: If you
expect lots of lightning in your area, take precautions with your electronic
equipment. Snap-on ferrites on the cords work well.


Tim Ressel--Compliance Engineer
Hewlett-Packard
Verifone Division
3755 Atherton Rd.
Rocklin, Cal
916-630-2541  
timothy_ressel at hp.com



-----Original Message-----
From: Rory McDonald [mailto:RMcDonald at wireone.com]
Sent: Wednesday, August 02, 2000 7:40 PM
To: synth-diy at node12b53.a2000.nl; 'oldsynth at egroups.com'
Subject: Lightning


I just saw an interesting piece on Lightning striking humans on CNBC and
made me wonder-is Lightning AC or DC? I know that the voltages can be huge.
Some woman on the show got hit 3 times in her lift and lived to tell the
tale-yikes!
Rory