Timeline for Why doesn't electricty flow to earth ground when I connect my oscilloscope ground clip to a floating circuit?
Current License: CC BY-SA 4.0
8 events
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| Oct 23, 2020 at 6:22 | comment | added | alejnavab | @VoltageSpike "the air can actually conduct a small amount of electrons" Really? (I'm not being sarcastic) How? | |
| Sep 26, 2019 at 2:20 | comment | added | Voltage Spike♦ | Depends, are you talking a real world cap or an ideal cap, or an ideal wire or real world wire. An ideal wire the wire will be the exact voltage of whatever it's connected to. A real wire will have a small current, becasuse there a small amount of capacitance between it and the other end of the wire, so it's like two capacitors in parallel with a switch between them. But in the real world there will be a small amount of time and then it to will be the same voltage as the capacitor. | |
| Sep 26, 2019 at 2:14 | comment | added | Jakub Arnold | But why must I have a closed connection? If I were to take a loop of wire around a capacitor (to make them equal potential), cut the wire on both ends, charge the capacitor separately on a battery, disconnect it from the battery, and then connect one end of the first write to one end of the capacitor, there must be at least some current flow. If nothing else, the bunched up electrons in the capacitor that didn't have anywhere to go beforehand now had a lot more area to spread out in the wire ... and as a result, there would be current flow in the wire, no? | |
| Sep 26, 2019 at 1:59 | comment | added | Voltage Spike♦ | It doesn't matter what circuit you have, you must have a closed connection or no current will flow. There must be a return path for the current | |
| Sep 26, 2019 at 1:38 | comment | added | Jakub Arnold | Sure but I don't mean the case when we close a circuit using ground. I mean a circuit where only one earth ground connection is made. Why is it that a floating capacitor lead can sink 0 amps, when you earlier said that everything has parasitic capacitance, including the other leg to the environment and rest of the circuit. | |
| Sep 25, 2019 at 18:22 | comment | added | Voltage Spike♦ | The earth can sink very large currents, 1000's of Amps. A capacitor lead that is floating can sink 0 Amps. Earth can complete a circuit, meaning if you have two things that are plugged into earth ground current can flow through the earth like a wire | |
| Sep 25, 2019 at 18:02 | comment | added | Jakub Arnold | In the capacitor case, you say "there is no other node for current to flow into", but isn't that the same case as with earth ground, except that the wire at the end of the capacitor has much lower ability to absorb charge? I do understand that these values are probably small and practically insignificant, but I'm having a real hard time wrapping my head around "no current because not closed", and when do these things actually become large enough currents to possibly break something ... like when I touch a charged capacitor with my ground clip, or something like that | |
| Sep 25, 2019 at 17:28 | history | answered | Voltage Spike♦ | CC BY-SA 4.0 |