Re: Opinions on Oscilloscopes

tekamn wrote: 
RR wrote:

"Jim Yanik" <jyanik@xxxxxxxxxx> wrote in message
news:Xns96E0BE03CB84Djyanikkuanet@xxxxxxxxxxxxxxxxx

Scope input is rated *DC plus peak AC*.
At least that is how Tektronix specs their scopes.
Why are you going to put 250VAC into the TRIGGER input? The scope usually
has an internal trigger pickoff AFTER the attenuator,to keep trigger
signals small  but useable. External trigger is used when you have a clean
reference signal to use,like H or V drive from a video generator when
looking at composite video,eliminates the need for a sync spearator..


Down the track (lots of learning to do), I'm interested in creating and/or
working with alternative power sources (solar to battery then inverted to
mains power).

I know I'll probably buy a lot of the equipment for doing this, but it
always helps if you understand the circuit, especially when it stops
working.

So, if the input is 12VDC and the output is 240VAC, I suspect I'm going to
need to put a scope on both sides at some stage.

I'm just thinking ahead, and maybe I'll never need to look at mains through
the scope.

And even if I do, I may have bought a much better scope by then.  Besides,
my research indicates that differential probes are specifically designed for
looking at high voltages (hence putting that question in my OP).

thx,
RR




If you think about the 12V DC/240V AC setup, then go thais way for a
solution: 2 ch scope with HV isolator (e.g. Tektronix A69xx or
something like this, Jim please help my memory and give the right
description).


There's an A6902A for sale here:
http://nm7u.tripod.com/homepage/te.html


You will not go wrong with a Tektronix, but besides all "patience" that
was recommended in buying: A good working well kept Tektronix is all
time more expensive than a worn out one that (might) need maintenance.

Keep this in mind when you compare a price offer, and don't simply go
for a low price -- your mileage may vary.


A lot depends on where you live. I'm surely not typical, but I've had to repair almost every scope I've purchased. And the ones advertised as
"works perfectly" often took more time and $$ to repair as the ones advertised as "dead".

The most important information about a used product is, "Have they tried to fix it?" I've had good luck with busted stuff from people who don't know anything about it. I've had BAD luck with "needs minor repair" stuff from experts, or from hamfisted repairers. This goes for test equipment, cars, washing machines...
I've also had some very interesting email discussions with a well-known equipment refurbisher who advertises stuff on EBAY as "no way to test it"
under an email address that looks like an individual. They routinely
calibrate this stuff. Why would they advertise it as untested???
And why would they vanish when you called them on it?

So, bottom line (for me) is, "Price is THE ONLY object." Assume everything is busted and offer accordingly. YMMV.
mike


hth,
Andreas




--
Wanted, Serial cable for Dell Axim X5 PDA.
Return address is VALID but some sites block emails
with links.  Delete this sig when replying.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/

.

Relevant Pages