| ??? 07/10/05 12:07 Read: times |
#96955 - Sort of. Responding to: ???'s previous message |
Kai Klaas said:
....because in many countries phone lines and earth potential of households are totally separated. This can result in heavy overvoltages (surges, burst, etc.) between phone lines and earth potential, especially due to lightnings! Are you sure Kai ? I would have thought it is probably always "grounded" , sort of,nominally, somewhere, once ! For instance, You can have the system "tied to ground" at the exchange, and behaving perfectly fine, until a lightning strike raises LOCAL earth potential some considerable distance above ground. I agree that strenuous efforts need to be taken to deal with transients though. Steve |
| Topic | Author | Date |
| First:Wiring Error Detection! | 01/01/70 00:00 | |
| It depends | 01/01/70 00:00 | |
| First observation | 01/01/70 00:00 | |
| First observation | 01/01/70 00:00 | |
| Danger of surges | 01/01/70 00:00 | |
| Sort of. | 01/01/70 00:00 | |
| Sort of | 01/01/70 00:00 | |
| Re: Sort of... | 01/01/70 00:00 | |
| Phone line transients | 01/01/70 00:00 | |
| Schematic of a simple filter | 01/01/70 00:00 | |
| Research... | 01/01/70 00:00 | |
| router | 01/01/70 00:00 | |
| gas discharge tubes | 01/01/70 00:00 | |
| GDT | 01/01/70 00:00 | |
| Gas discharge tubes | 01/01/70 00:00 | |
| Oh dear... | 01/01/70 00:00 | |
| Gas Tubes | 01/01/70 00:00 | |
| Or | 01/01/70 00:00 | |
| Ring. | 01/01/70 00:00 | |
| Where's Ring? | 01/01/70 00:00 | |
| I say .. | 01/01/70 00:00 | |
| Telephone systems | 01/01/70 00:00 | |
| Telephone systems | 01/01/70 00:00 | |
| tester | 01/01/70 00:00 | |
| Yep Jan! | 01/01/70 00:00 | |
| Even for testing not allowed | 01/01/70 00:00 | |
| Line simulator | 01/01/70 00:00 | |
| Another Misunderstanding Kai | 01/01/70 00:00 | |
| misunderstanding | 01/01/70 00:00 | |
| Jan | 01/01/70 00:00 | |
| Confusion... | 01/01/70 00:00 | |
| quote from my previous post | 01/01/70 00:00 | |
| It's a current loop ... | 01/01/70 00:00 | |
| Correction | 01/01/70 00:00 | |
| ring? | 01/01/70 00:00 | |
| Yes Jan! | 01/01/70 00:00 | |
| Agreed | 01/01/70 00:00 | |
| it explains a few things, though | 01/01/70 00:00 | |
| Phone Line Ground | 01/01/70 00:00 | |
| Not quite offtopic... | 01/01/70 00:00 | |
| Alternative schematic | 01/01/70 00:00 | |
| Just a simple comparsion !!!!!!!!!!!!!!! | 01/01/70 00:00 | |
please help me (telepone) | 01/01/70 00:00 |