Earthed Oscilloscope

Discussion in 'Electronics Resources' started by andyb510, Jan 6, 2014.

  1. andyb510

    Thread Starter New Member

    Jan 6, 2014
    Hi anyone, can someone advise me please. I have purchased a handheld Hantek oscilloscope and I am reading up on how to use them before it arrives. I was lead to believe that since the scope will be floating as it is not earthed I should not run into any major problems shorting things out. Then I read somewhere else that this is bad practice and should earth my scope to protect myself. can someone please help me to clarify this. Do I need to earth my portable scope when doing readings?.
  2. MrChips


    Oct 2, 2009
    It depends on the application and situation.

    If the circuit you are monitoring is powered at low voltages, say 24V or less, then it is less of a concern.

    Most voltage measurements in an electronic circuit are taken at a node with respect to a COMMON reference point which is usually at ground potential. Hence in such cases you want your scope to be grounded.

    The few times that it is advantageous to have a floating scope is when you wish to measure the potential difference across a component, for example, if you wish to measure the current pulse on the high side of a power supply.

    If you are doing this on a high voltage supply then yes, the scope can be at a lethal potential.

    In summary, yes you are more likely to be using the scope with the ground clip at GROUND.

    In all cases, be aware of what you are doing.
  3. andyb510

    Thread Starter New Member

    Jan 6, 2014
    Many thanks for your reply. I am trying to learn about solid state guitar amplifiers, where I guess I will be dealing with high voltages I think. would be nice if there was books or videos with someone showing you where to take reading from on the board. this is hard to find.

    Will I be okay as long as I stick to the secondary side and use a DMM for the primary?
  4. alfacliff

    Well-Known Member

    Dec 13, 2013
    switching power supplies usually arent grounded on the input side. a scope qith a ground will cause a big problem if trying to get waveforms of a pwm chip or mosfet on teh primary side. the secondary side is usually grounded. linear supplies are ground refferenced on the primary side. use caution when using a scope around high voltages, read the precautions and ratings of the probes you will be using too.
  5. atferrari

    AAC Fanatic!

    Jan 6, 2004
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