o-scope

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Sun May 6 11:40:03 2001

From: Jim Strickland <jim_at_calico.litterbox.com>
>So I'm a 'scope newbie, does the probe impedance (13 pf) have to match
the
>rating on the jack on the scope (47 pf) for the waves coming out of the
>calibration jack to be properly square? And if so, does anyone have a
source
>for probes that work with ancient scopes like this?


No not required to match. That specification is the capacitance
presented
across the input jack along with the scopes input resistance (usually
1megohm).
Most scope probes have an adjustment to compensate for this and therefor
it's not a problem.

>Other than the waveform distortion (at worst the square waves wind up
looking
>like shark teeth, and at best they're a bit sloped on the leading and
top
>edges) the scope seems to work fine as far as I can tell.


Probe compensation is off or the amplifier (vertical) are misadjusted
internally.

A square wave on that series should look square.

Allison
Received on Sun May 06 2001 - 11:40:03 BST