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AC line detection

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DarioG
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RE: AC line detection 2007/01/26 09:45:38 (permalink)
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I *did* take a look at it.
Sounds nice I'll keep it in mind next time I need such a thing.

Thx!

GENOVA :D :D ! GODO
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nidal
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RE: AC line detection 2007/01/27 12:14:36 (permalink)
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Thank you friends,
I will try my relay now, if I had problem I will use your ideas.
 
thank you alot
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Pepperysteve
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RE: AC line detection 2007/01/29 14:19:09 (permalink)
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Hi drh,

The Fairchild MID400 looks to be a nice single-chip solution. Like Dario, I have not used this device before but it looks like it has good potential for use for future designs.

I do not know what the experience/skill level of the OP is but this looks like a nice easy way to integrate AC line detection with a handful of parts.


Steve
#23
TechnoCat
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RE: AC line detection 2007/01/29 14:50:13 (permalink)
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I would use 2 or 3 resistors in series, one >1MR at the AC power, so that the wire coming into the board is relativly safe, and another on the board itself, be sure to use resistors rated for high voltage, normal 1/4 w resistors arnt safe enough for this, you can easily get voltage spikes on mains AC wich exceed 1kv, ive worked on several mcu projects wich have VSS at either mains N or negative of rectified mains wich is rather hairy to work on. its best to put catch diodes wich act in parallel with the on chip diodes, schotky would be ideal, its also best to put a zener accros the mcu supply so if the cpu is idle the VDD cant be pushed up by the current through the catch diode, another alternative is just to put 2 zener diodes as catch diodes, although zeners need a significant current before they reach their nominal voltage, there are altarnatives.
 
The opto idea suggested earlier is also a good idea, but you stil end up with mains and low voltage on the same board.

=^.^=
#24
drh
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RE: AC line detection 2007/01/30 08:46:11 (permalink)
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There is very useful application note for the MID400 on the fairchild website, AN-3007.
 

David
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