| ??? 02/22/10 18:23 Modified: 02/22/10 18:31 Read: times |
#173436 - two wrongs Responding to: ???'s previous message |
It may be a "bad idea (!)" to connect live 220V ditrectly to the micro. I think I can do the same thing to one of the input pin of an op-amp and use its output through an optocoupler to annunciate the ZERO-CROSSING of the ac line. I think this method will sense ZERO-CROSS quicker than other methods at the same time will be less hazardous and less dangerous.
two wrongs first, you are still connected live to the mains (or how else will you power the OP-amp) second, not an OP-amp, but a comparator it is dead easy to protct the Micro (e.g. a HC chip will do), but the issue is protecting you!!! from electrocution and lawsuits from descendants of electrocuted customers. Erik |
| Topic | Author | Date |
| Zero crossing detector - technique adoption | 01/01/70 00:00 | |
| Sounds like a bad idea to me! | 01/01/70 00:00 | |
| relying on parasitic diodes | 01/01/70 00:00 | |
| Confusing | 01/01/70 00:00 | |
| I mean | 01/01/70 00:00 | |
| Designing to typical values | 01/01/70 00:00 | |
| what blather | 01/01/70 00:00 | |
| " IDEA ? " - RIDICULOUS | 01/01/70 00:00 | |
| at least for this one | 01/01/70 00:00 | |
| Oh dear: | 01/01/70 00:00 | |
| tough, but true | 01/01/70 00:00 | |
| just caught this one | 01/01/70 00:00 | |
| Idiom | 01/01/70 00:00 | |
| It really is a *very* bad idea! | 01/01/70 00:00 | |
| Don't blindly follow app note | 01/01/70 00:00 | |
| It's not so much the parasitic diodes... | 01/01/70 00:00 | |
| two reasons | 01/01/70 00:00 | |
| What should I do ... | 01/01/70 00:00 | |
| That won't help at all! | 01/01/70 00:00 | |
| two wrongs | 01/01/70 00:00 | |
| Most app-notes don't work ... because they're wrong! | 01/01/70 00:00 | |
| This is typical ... | 01/01/70 00:00 | |
| I hate to tell this,... | 01/01/70 00:00 | |
App engineers not always the sharpest tools in the shed | 01/01/70 00:00 | |
| Unbelievable!! | 01/01/70 00:00 |