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Scarr said:forgot to mention, I am using a PIC could zero crossover of AC mains be detected using the PIC somehow?
Thanks
Exo said:This is a application note for a 12c508 based light dimmer. It also contains zero crossing detection
https://www.electro-tech-online.com/custompdfs/2004/10/40171a-1.pdf
Scarr said:OK, first, thanks Nigel
I am happy with either half or full cycles, I have been looking whilst wating for a reply and this whole zero-crossover is a nightmare!!!!
I am looking for the simplest way to determine the actual zero voltage point, will using a PIC pin give me this? if so can you point me at the microhip article that shows this?
Thanks
Optikon said:Not to be picky, but the app note method will determine the zero-crossing only to the level of the input threshold of the logic buffer. Despite the fact you mention _actual_ zero crossing, I assume you would be ok with this voltage and not actually zero volts.
Scarr said:I am acutally wanting to dectect as close to the zero volts as posible so anything that puts a slew on this I need to know about, this is why I was looking for a IC to give me a nice pulse / square wave. as neear to zero as possible and without many external components
I have found the UAA2016P will this do the job?
JohnBrown said:Nigel, just out of general interest, isn't there a 90 degree phase shift between the input and output of a transformer?
Nigel Goodwin said:Optikon said:Not to be picky, but the app note method will determine the zero-crossing only to the level of the input threshold of the logic buffer. Despite the fact you mention _actual_ zero crossing, I assume you would be ok with this voltage and not actually zero volts.
Every component you use is subject to tolerances, there shouldn't be any problem with the zero-crossing point being subject to similar tolerances. Generally all you need is a reliable, repeatable, switching point close to the actual zero-crossing.