Timeline for Voltage propagation along a wire [closed]
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| S Aug 8, 2019 at 12:50 | history | closed |
BioPhysicist Chris♦ |
Not suitable for this site | |
| S Aug 8, 2019 at 12:50 | comment | added | Chris♦ | I'm closing this question because it has been reposted at EE.SE. | |
| Aug 7, 2019 at 21:24 | comment | added | pipe | Cross-post here electronics.stackexchange.com/questions/452006/… | |
| Aug 7, 2019 at 19:41 | comment | added | The Photon | How to get the signal stable at 2 before 1: Use a source-terminated system. Match the source impedance to the line, but leave the far end open. Now at 1 you see the outgoing wave but have to wait for the reflection being returned before the signal will reach its final value.. At 2 the returned reflection arrives sooner than at 1, so 2 gets to its final value before 1 does. | |
| Aug 7, 2019 at 19:36 | comment | added | PistoletPierre | Thanks; will take a look. | |
| Aug 7, 2019 at 19:30 | review | Close votes | |||
| Aug 8, 2019 at 12:55 | |||||
| Aug 7, 2019 at 19:01 | comment | added | The Photon | Related on EE: Do long transmission lines degrade rise/fall times, and if so, by what mechanism? | |
| Aug 7, 2019 at 19:00 | comment | added | PistoletPierre | Uhh wow. Ok, I wasn't expecting that last sentence. Could you elaborate? | |
| Aug 7, 2019 at 18:57 | comment | added | The Photon | Whether the signal at #1 gets stable depends on whether you've designed your wire as a controlled-impedance transmission line, and how well matched the termination is at the end of the line. I could design it so that the signal at #2 becomes stable first, if I wanted to. | |
| Aug 7, 2019 at 18:40 | comment | added | PistoletPierre | @SamuelWeir I have a (relatively) long wire in a digital circuit where #1 and #2 are gate inputs that I want to act on with a picosecond-scale time gap between them; would #1's signal be stable before #2's was stable in the event of a change of voltage on the wire? Like, is this feasible or am I barking up a silly tree? (EDIT): I've confirmed that I can delay a signal by a few picoseconds by lengthening a wire from point A to point B. But I want to know if I can get from point A to point B_1 in time_x and point B_2 in time_x + time_y just by spacing them out on the same wire. | |
| Aug 7, 2019 at 18:27 | comment | added | PistoletPierre | @SamuelWeir let's say you go from low to high. Once #1 sees high voltage, would it ever see low voltage again? Or would it see high voltage, and then when the reflection comes back, see momentarily super-high voltage? | |
| Aug 7, 2019 at 18:24 | comment | added | user93237 | Yes, the voltage change will travel down the line as a fairly sharp rise in voltage, and then will reflect off the far end of the wire and then propagate back to the voltage source and will (in general) reflect off it and then back towards the far end of the wire where it will reflect again, etc.. This process of multiple reflections will go on many times until the voltage is fairly uniform and constant across the length of the wire. This can all happen in a very, very small fraction of a second. Google information on "transmission line theory". | |
| Aug 7, 2019 at 18:20 | review | First posts | |||
| Aug 7, 2019 at 19:31 | |||||
| Aug 7, 2019 at 18:17 | comment | added | Sebastian Riese | Take a look here: en.wikipedia.org/wiki/Telegrapher%27s_equations | |
| Aug 7, 2019 at 18:16 | history | asked | PistoletPierre | CC BY-SA 4.0 |