Linked Questions

4
votes
4answers
1k views

Is it safe to remove earthing from a scope? [duplicate]

I need to make some differential measurements on a device, but both nodes need to be floating from earth. I found out the hard way that the negative clip of my oscilloscope voltage probes are ...
60
votes
9answers
32k views

Why on earth are o-scopes earth referenced?

Thinking about it: You would never find a "Grounded" multimeter as robust and useful if a path to ground through the multimeter were introduced, modifying the circuit's behaviour and possibly damaging ...
64
votes
3answers
96k views

How is using a transformer for isolation safer than directly connecting to the power grid?

How is using a 1:1 transformer safer than using the mains straight off? Is it because you can limit the current coming from the transformer whereas straight from the mains its not current limited? I ...
15
votes
6answers
37k views

Using oscilloscope safely with AC mains

I know there is quite few discussions already on this topic, but since english isn't my first language I though it better to get some more information about this. I have used oscilloscopes to ...
8
votes
4answers
3k views

Why does Oscilloscope cause short?

I want to measure how much power my PIC is using. At the output of my 3.3V regulator I put a 1 ohm resistor in series with the rest of the circuit. I was going to measure the voltage drop across that ...
7
votes
5answers
2k views

Using DC voltage instead of AC to supply SMPS

Situation: You have a battery pack with voltage of 300V. You have some appliances designed for 250V AC. These appliances have SMPS inside. Claim: Instead of using DC to AC inverter, you can use DC ...
7
votes
2answers
3k views

Isolation transformer and scope when troubleshooting SMPS

I have a simple question, when troubleshooting a SMPS is highly adviced to use an Isolation transformer. But my question is this, if im using a scope to troubleshoot the "hot" side of my SMPS, both ...
6
votes
3answers
5k views

home brew isolated oscilloscope lead

The ground clip for an oscilloscope lead is normally connected within the instrument to the power supply earth, and there are surprising circumstances where this could matter. The situation is very ...
3
votes
3answers
897 views

Oscilloscope for troubleshooting higher voltages?

I'm working on a friends inoperative Miller 300 Amp DC inverter Tungsten Inert Gas (TIG) machine. These machines convert 240v single phase A/C to DC, then use IGBT chips to generate controlled DC ...
0
votes
2answers
2k views

To avoid oscilloscope ground short, why not simply unground the scope? [duplicate]

We all know what happens when we ground a regular oscilloscope probe at the wrong place: a short. There are two main points to consider: 1) All channels share the same ground plane, so we can't take ...
0
votes
2answers
672 views

Power cord without ground cable

Ground cable was ripped from the power cord of most expensive oscilloscope in the lab . Neutral and line cables are stil there . Do you think this is done on purpose ? if so , why ?
3
votes
1answer
869 views

Oscilloscope ground clips sparks while connecting to power supply

Oscilloscope ground clips sparks while connecting to power supply ground. I do understand The clip is connected to earth ground. But why does it not spark when I am powering a circuit of the supply?
0
votes
3answers
1k views

Oscilloscope ground clip : short circuit

I'm measuring voltage on an audio amplifier mono output. Amplifier is powered using a stabilized power supply. I connect oscilloscope ground probe to one of the two output wire and a probe to another. ...
0
votes
2answers
584 views

Oscilloscope ground and unit under test ground issue

I am working with an instrument which has a supply of 230V AC or 400V DC. AC source is isolated at the input via 1:1 transformer and DC source is a floating supply. I have a Yokogowa DL1620 ...
0
votes
2answers
294 views

Oscilloscope measurements on device connected to a AC/DC wall-plug

I had a discussion with my colleges regarding Oscilloscope measurements and DUT (device under test) isolation. Specifically a device connected to a AC/DC wall-plug. I think I am aware of the concepts ...

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