| ??? 07/10/05 11:28 Read: times |
#96953 - Danger of surges Responding to: ???'s previous message |
Mehdi said:
When your telephone is in on-hook state the "TIP" is at about 0v, while "RING" is about -48v with respect to earth ground. This is a problematic assumption, Mehdi, 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! So, if your idea will work at all, you urgently need surge protection at input of your circuit. I will look into my archive in order to find a suited filter. Kai |
| 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 |