Scope and DC reading question

Discussion in 'General Electronics Chat' started by electronewb, Apr 26, 2012.

  1. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    I read AC no problem on my scope but for some reason when it comes down to DC I have to push the TV Line PP button on the trigger section. Why is that? I have a Tektronix 2221A

    Thanks
     
  2. mlog

    Member

    Feb 11, 2012
    276
    36
  3. electronewb

    Thread Starter Member

    Apr 24, 2012
    260
    3
    I looked into the manual but I guess I didn't see it. My friend has a different Tektronix an older model as well and as far as I can remember all he as to do is flip to DC on the channel input he doesn't have to use the trigger
     
  4. crutschow

    Expert

    Mar 14, 2008
    12,988
    3,226
    On most scopes if the trigger mode is set to NORM or AC or DC it will not trigger unless there is an AC waveform. If the trigger mode is set to AUTO then it will provide a baseline trigger even with a DC or no input.

    Your friend likely has his scope trigger set on the AUTO position if he doesn't have to change it when going from an AC to a DC input.
     
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