Connect with us

Measuring ground voltage.

Discussion in 'Electronic Basics' started by [email protected], Jan 25, 2006.

Scroll to continue with content
  1. Guest

    Hi All,

    I have a embedded system that includes CPU/RAM/FLASH/UART/Wireless
    Chip... etc.

    When I measured the voltage of ground:

    Scope's gnd point to ground A, another point ( red, should I say
    postive measuring point?) point to another ground - B ( but they should
    be the same voltage )


    When my system is running, decoding/transmitting ...etc, I can see the
    voltage of ground is abruptly changing,..., not keep in the 0V.

    Does it correct? and Why? should I add more circuit to stabilize it ?

    Best regards,
    Boki.
     
  2. Noway2

    Noway2 Guest

    In order for digital logic to operate correctly, a properly designed
    power and ground system is required.

    How is the ground in your system constructed? Are you using
    'serpentine' traces or are you using a solid ground plane? What do you
    have for bypass capacitors?

    The high speed (frequency) components of your digital siganls, due to
    the rise and fall of the signals, not the clock speed, follow the path
    of least inductance compared to the lower speed portions which follow
    the path of least resistance. A solid ground plane is usually required
    to achieve a low inductance ground system. If you used serpentine
    traces you may be very surprised at the paths taken by your ground
    currents.

    Measuring the noise on a ground system can be trickier. You will run
    into problems with the loop inductance of your probe, especailly if you
    attempt to use a probe cap on a 10x probe and a flying ground lead.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-