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Micsig Tablet Oscilloscope tBook mini TO1104 review (100Mhz 4 channel 'scope)
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tautech:

--- Quote from: alm on July 04, 2017, 02:11:55 pm ---
--- Quote from: tautech on June 28, 2017, 05:44:11 am ---As it's not mains ground referenced some use it like an isolated channel scope; that is with the signal reference at elevated voltages. Would you trust a wallwart for this use case or prefer complete removal from any external power source ?

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I do not understand your point. Either you trust the isolation of the channels, which means the scope should be safe to touch, and the power supply does not have to provide any isolation beyond mains, or you do not trust the isolation and you should not touch the scope at all during elevated measurements. In the latter case, you probably should not use it for floating measurements at all, even on battery power.

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As the question was about using it just mains (walwart) powered or getting the battery, it's clear to me that the intention is to use it floating where maybe it's not designed for such use, however many do.
If one was using any HH at elevated reference voltages wouldn't it be wise to have it battery powered ?

You can't trust anything that is not expressly written in the specs........elevation above surroundings,mains Gnd, max voltages etc.
With isolated channel scopes all these specs are listed, SHS1000 models:

CATII 1000V and CATIII 600V between two channels references?between channels reference and earth ground
CATII 600V and CATIII 300V between channels reference and Multimeter input reference
CATII 300V and CATIII 150V input direct
CATII 1000V and CATIII 600V input with 10?1 probe (supplied probe)
alm:
Ah, it is a non-isolated handheld/tablet. I missed that, my bad. Interesting how they discuss floating measurements in the manual for their handheld MS2xx series, and how if should be limited to 42Vpeak and 36Vrms, but not for the tablet scopes. The document about tablet scope safety is obviously 404 (not found) :P. Are they expecting the tablet scopes to usually be grounded?

I am not sure if using a battery would make it any safer. If you manage to float the instrument so far above ground to break down the insulation of the power supply (are they not hipot-tested to something like 1.5 kV?), then I am not sure if a dead power supply is the worst of your worries. At least then the GFCI (if present) might trip. There is of course the issue of the insulation resistance of the power cord. If you limit the floating voltage to sensible levels as suggested in the MS2xxx manual, then I do not see how battery vs wall wart makes a difference. I am also not sure if suggesting floating use to beginners, if the manual does not mention it at all, is wise.
tautech:

--- Quote from: alm on July 04, 2017, 09:42:26 pm ---Ah, it is a non-isolated handheld/tablet. I missed that, my bad. Interesting how they discuss floating measurements in the manual for their handheld MS2xx series, and how if should be limited to 42Vpeak and 36Vrms, but not for the tablet scopes. The document about tablet scope safety is obviously 404 (not found) :P. Are they expecting the tablet scopes to usually be grounded?

I am not sure if using a battery would make it any safer. If you manage to float the instrument so far above ground to break down the insulation of the power supply (are they not hipot-tested to something like 1.5 kV?), then I am not sure if a dead power supply is the worst of your worries. At least then the GFCI (if present) might trip. There is of course the issue of the insulation resistance of the power cord. If you limit the floating voltage to sensible levels as suggested in the MS2xxx manual, then I do not see how battery vs wall wart makes a difference. I am also not sure if suggesting floating use to beginners, if the manual does not mention it at all, is wise.

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Yes of course.

There is a lot more interest in HH/tablet DSO's primarily for one reason....they can be floated if required. Some of this stems from ongoing discussion of this topic and a greater awareness of different measurement techniques.
Dave's vid on 'How to not blow up your scope' alerted many to the traps of scope measurements.....common knowledge for those that have been around a while with scopes........ and now buyers are looking for other solutions to this age old problem.
Rather that spend more for truly isolated channel DSO/HH's or a set of differential probes many are opting for HH's and floating them............whether we like this or not.
As users get a handle on floating scopes they WILL start to push the float voltages higher, of course at their peril and the likely causes of problems......PSU and USB connections need be identified and not used at elevated reference voltages.
fishandchips:
Excuse me. What is mean by "floating" the scope?
TK:

--- Quote from: fishandchips on July 05, 2017, 12:47:12 pm ---Excuse me. What is mean by "floating" the scope?

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Removing the GND in in the AC plug so the oscilloscope ground is not connected to earth.  It is a very bad and dangerous practice.
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