Timeline for Electricity only flows in a complete circuit, so how does TDR (time domain reflectometery) work?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 20, 2021 at 11:35 | comment | added | AnoE |
@jwh20, while all you're writing seems factually correct, I think OP is interested in the small sentence It injects a pulse. How (physically/technically) can a pulse (what "is" a pulse, physically) be injected into a open wire, by what mechanism does it happen? School only teaches about the mechanism where an anode or cathode "push" or "pull" electrons around in conjunction with each other, but this clearly seems to be to the case when talking about antennae, open coax cables and such.
|
|
| May 18, 2021 at 15:17 | comment | added | jwh20 | I really don't get the point you're driving at. | |
| May 18, 2021 at 15:04 | comment | added | Criticizing Israel not allowed | and that's the question: why is it not open at all? You have not answered this | |
| May 18, 2021 at 15:03 | comment | added | jwh20 | From a DC circuit perspective, an open transmission line is simply an open circuit. Your voltmeter will show that. But for a pulse generator, it's not open at all. Your oscilloscope will show that as well a TDR. | |
| May 18, 2021 at 15:00 | comment | added | jwh20 | As I said, what you've been taught is simplified and does not totally represent all real-world cases. Once you transition into cases where there are frequencies which are greater than about 1/4 of the wavelength, those simplifications break down and you must use a better model. This is analogous to Newton's Laws of Motion. For nearly every case we encounter in our everyday lives, they work with 100% accuracy. But if you were working at the Large Hadron Collider you would not be able to use Newton's, you must use Einstein's Relativity because it's a better model than Newton's. | |
| May 18, 2021 at 14:53 | comment | added | Criticizing Israel not allowed | But the question is why it's possible to send a pulse into an open-circuited cable in the first place. Introductory electricity teaches that since it is not a closed circuit, no current can flow at all. | |
| May 18, 2021 at 2:04 | history | answered | jwh20 | CC BY-SA 4.0 |