| ??? 02/15/06 03:01 Read: times |
#109998 - Yes, but... Responding to: ???'s previous message |
Mahmood said:
Why not use normally closed realy contacts for the alarm and have the coil 220VAC,... Yes, this is a good idea. But there's a trap: Relays with a working voltage of 230VAC often show very robust contacts, which cannot reliably switch very light loads (dry loads). So, when using such a relay you either get contact problems or you need to increase the load, but that would increase current consumption of the supply voltage that is used for the switching. The transformer solution, on the other hand, would keep the current consumption to the absolute minimum and contact problems won't occur either. Regards, Kai |
| Topic | Author | Date |
| monitoring mains voltage | 01/01/70 00:00 | |
| Opto with capacitor | 01/01/70 00:00 | |
| re opto with cap | 01/01/70 00:00 | |
| Some protective components required | 01/01/70 00:00 | |
| Fire risk | 01/01/70 00:00 | |
| Transformer | 01/01/70 00:00 | |
| thats the best chioce | 01/01/70 00:00 | |
| There's nothing wrong | 01/01/70 00:00 | |
| Space | 01/01/70 00:00 | |
| please do not go aargh | 01/01/70 00:00 | |
| Opto isolator = LDR + Neon? | 01/01/70 00:00 | |
| 10mA? | 01/01/70 00:00 | |
| Hmmm | 01/01/70 00:00 | |
| Why not... | 01/01/70 00:00 | |
| Neon + Photodiode | 01/01/70 00:00 | |
| Loosing brightness | 01/01/70 00:00 | |
| Transformer isolation is needed! | 01/01/70 00:00 | |
| Previously, on 8052.com | 01/01/70 00:00 | |
| Safety first | 01/01/70 00:00 | |
| Transformer | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| two places to look | 01/01/70 00:00 | |
| Annoying, isn't it?! | 01/01/70 00:00 | |
| Thanx! | 01/01/70 00:00 | |
| maybe Amveco 6200 series? | 01/01/70 00:00 | |
| Transformers | 01/01/70 00:00 | |
| Could also be used | 01/01/70 00:00 | |
| an Idea | 01/01/70 00:00 | |
| The simplest ideas are the best | 01/01/70 00:00 | |
| Poor dads | 01/01/70 00:00 | |
| Tainted food | 01/01/70 00:00 | |
| Yes, but... | 01/01/70 00:00 | |
| Low current | 01/01/70 00:00 | |
Exactly! | 01/01/70 00:00 |