Jeff,
I don't know if the 7B92 is very much different from the 7B53 series, but from what I read, when in AUTO, if there's no trigger signal, a capacitor (C786) stays charged that keeps the MILLER RUNUP section enabled which causes a continuous sweep. In other words, a sweep in AUTO mode doesn't care whether the trigger is armed.
Someone please correct me, though, if that's wrong or if it's an over-simplification.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message -----
From: "Jeff Dutky" <jeff.dutky@...>
To: "tekscopes" <[email protected]>
Sent: Saturday, December 11, 2021 11:56:57 PM
Subject: Re: [TekScopes] Timebase Question : Auto vs Norm Mode
Barry,
though you did say to disregard this question, I will answer simply because it
will make the archived messages more useful to other people at a later time
(and because I have been looking at this in a 7B92, so I think I understand how
the free-running feature is supposed to work).
In AUTO mode the sweep will trigger when either of two things happens: 1. when
the trigger condition is met (and the trigger circuit is in the ARMED state),
or 2. when a timer (an RC circuit in the 7B92) finishes (and the trigger
circuit is in the ARMED state). This means that you get a short pause between
free-run sweeps if the trigger conditions are not met, so they will not
necessarily be happening at the specified sweep frequency (in other words, if
you set a sweep speed of 1 ms/div, so that the sweep takes something like 10
ms, the actual free-run rate may be something like 20 ms, or even slower
depending on the auto-sweep timing).
-- Jeff Dutky
