Hello, I read that measuring with an oscilloscope, you need an amplifier, you need galvanic separation, I ask from what point of view, when today's amplifiers have only 2 wires. Thank you for any knowledge
I believe the concern you're referring to is the risk of short-circuiting a mains-referenced component to the earthed chassis of the oscilloscope during measurement. If the oscilloscope is grounded to earth, then connecting its ground line to something with a potential to earth, it may result in a short-circuit being formed and resulting damage to the oscilloscope. There are a few solutions to this problem, including: 1. The use of an isolated oscilloscope probe, which measures and re-creates the target waveform through a galvanically-isolated barrier. 2. The galvanic isolation of the target device being measured, for example, by powering it through an isolation transformer or from a battery. 3. The galvanic isolation of the oscilloscope itself from earth ground, i.e., by removing the ground pin from the mains cable. Although it is not recommended, I typically use the 3rd method when I need to measure mains-referenced circuits using an oscilloscope. The risk with this method is that the entire scope, including other BNC jacks, USB ports, etc. all become mains-referenced when connected to the target device. This can be hazardous, but if you are aware of the hazard, it can be mitigated effectively. The safest and most industry-standard way to handle the issue of target device isolation would either be the 1st method (safest), or the 2nd method (less safe, but potentially less expensive than buying an isolated probe set).
that really great . but I need to know one thing .A person holding the drilling device let the fault occur in devices either a wire break. when the person touches the break point wat happens ??? no effect in body because secondary is not grounded ok. but the person standing in ground potential whether the person got grounded by body and get shock?????
If there is a path for current through the person's body (i.e., from the break point to a secondary-referenced surface) then they will receive a shock. Otherwise, no current will flow.
I've been scrolling through several videos trying to decide what to do with the ground leads. Of course you need to remove any strapping of neutral and ground on the secondary of the isolation transformer, but there seems to be controversy regarding what to do with the ground lead of the device under test (DUT). Some say to use an adapter that only allows connection of the two power leads, and others say it's better to preserve technician safety by continuing to ground the chassis of the DUT. Although that ground goes back to the circuit panel where neutral and ground are strapped, it's not the neutral of the secondary, it's the neutral for the primary. Of course the oscilloscope is plugged in to that circuit, so the ground for the oscilloscope frame will not be floating. What do you think?
spelunkerd In my next video where I show my homemade isolation transformer, I chose to leave all of the above options. I included a switch which allows the user to connect the DUT ground to either earth, floating, or directly to the transformer's secondary neutral. Thanks for watching, BTW!
Once you ground the chassis the circuit is "hot" any other point in the circuit is now at 120 V. SO you cannot touch anything other than the grounded point in the circuit. Had you not grounded the chassis you would be able to touch any one place in the circuit without shock. But having touched one point in the circuit it is NOW grounded and all other points in the circuit are now "hot." Of course you do not have to touch the circuit in order to ground and render every other point "hot." All you have to do is attach the ground clip of your scope anywhere and that point is now ground referenced. You can probe all other hot points to get voltage measurements in the circuit with the probe tip. You cannot attach a second ground clip (at the same time) to a different point in the circuit, however.
The second coil must be insulated very well, so that there will be no current transfer fault from the initial coil to the two through the metal
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wow, your explanation are easy to understand.. thank you sir.. you are an excellent teacher
Hello, I read that measuring with an oscilloscope, you need an amplifier, you need galvanic separation, I ask from what point of view, when today's amplifiers have only 2 wires. Thank you for any knowledge
I believe the concern you're referring to is the risk of short-circuiting a mains-referenced component to the earthed chassis of the oscilloscope during measurement. If the oscilloscope is grounded to earth, then connecting its ground line to something with a potential to earth, it may result in a short-circuit being formed and resulting damage to the oscilloscope.
There are a few solutions to this problem, including:
1. The use of an isolated oscilloscope probe, which measures and re-creates the target waveform through a galvanically-isolated barrier.
2. The galvanic isolation of the target device being measured, for example, by powering it through an isolation transformer or from a battery.
3. The galvanic isolation of the oscilloscope itself from earth ground, i.e., by removing the ground pin from the mains cable.
Although it is not recommended, I typically use the 3rd method when I need to measure mains-referenced circuits using an oscilloscope. The risk with this method is that the entire scope, including other BNC jacks, USB ports, etc. all become mains-referenced when connected to the target device. This can be hazardous, but if you are aware of the hazard, it can be mitigated effectively.
The safest and most industry-standard way to handle the issue of target device isolation would either be the 1st method (safest), or the 2nd method (less safe, but potentially less expensive than buying an isolated probe set).
@@DielectricVideos verry thanx
Great video...the drawings help a bunch! Thanks!
the fault current will pass through his body to the ground since he his standing on the wet ground and get electrocuted.
nice explanation!
Clear explanation. Thanks!
Thank you
that really great . but I need to know one thing .A person holding the drilling device let the fault occur in devices either a wire break. when the person touches the break point wat happens ??? no effect in body because secondary is not grounded ok. but the person standing in ground potential whether the person got grounded by body and get shock?????
If there is a path for current through the person's body (i.e., from the break point to a secondary-referenced surface) then they will receive a shock. Otherwise, no current will flow.
I've been scrolling through several videos trying to decide what to do with the ground leads. Of course you need to remove any strapping of neutral and ground on the secondary of the isolation transformer, but there seems to be controversy regarding what to do with the ground lead of the device under test (DUT). Some say to use an adapter that only allows connection of the two power leads, and others say it's better to preserve technician safety by continuing to ground the chassis of the DUT. Although that ground goes back to the circuit panel where neutral and ground are strapped, it's not the neutral of the secondary, it's the neutral for the primary. Of course the oscilloscope is plugged in to that circuit, so the ground for the oscilloscope frame will not be floating. What do you think?
spelunkerd In my next video where I show my homemade isolation transformer, I chose to leave all of the above options. I included a switch which allows the user to connect the DUT ground to either earth, floating, or directly to the transformer's secondary neutral.
Thanks for watching, BTW!
Once you ground the chassis the circuit is "hot" any other point in the circuit is now at 120 V. SO you cannot touch anything other than the grounded point in the circuit. Had you not grounded the chassis you would be able to touch any one place in the circuit without shock. But having touched one point in the circuit it is NOW grounded and all other points in the circuit are now "hot." Of course you do not have to touch the circuit in order to ground and render every other point "hot." All you have to do is attach the ground clip of your scope anywhere and that point is now ground referenced. You can probe all other hot points to get voltage measurements in the circuit with the probe tip. You cannot attach a second ground clip (at the same time) to a different point in the circuit, however.