Re: Streamer formation on the scope...

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


Terry,

Some transmission line questions...

20-30 nSec is about the round trip time in 6 feet of cable (1 ft/nsec one 
way, in space... 20 nsec = 10 feet round trip in free space, 6-7 feet with 
velocity factors in 60-70% area). Capacitive loading always seems to make 
the round trip time a bit longer.

How long is the coax from the current probe to the scope?  Is the probe a 
50ohm device feeding a 50ohm scope or is it a voltage source feeding a 1Meg 
scope?  What sort of coax is it (the really low C, low microphonic scope 
probe stuff, or something like RG174/RG58)

A quick way to disambiguate measurement cable artifacts from real stuff is 
to change the cable length by about 30%.. (you don't want twice or half...)

Also, another quick check is leaving the cable and the probe in the same 
place, but disconnecting it from the UUT (in the case of a I probe, remove 
the current carrying wire.. in the case of a V probe, disconnect and 
connect a few hundred ohm resistor across it)