tocki frequency

[chrispol]

I'm looking to read the frequency of a 6v ac signal for zero crossing from what i understand i can get away with a from ra4 to vdd and a 100r from 6vac to ra4 then i just use timer0?

[mister_e]

Yup but 100 Ohm is probably too low. 6 Vac gives about 9Volts in Peak. 9/100=90ma... i'll prefer to use something like an 1K.

Probably the following post i did few times ago can help. It's a simple frequency counter.
http://www.picbasic.co.uk/forum/showthread.php?t=1044

[chrispol]

Yup but 100 Ohm is probably too low. 6 Vac gives about 9Volts in Peak. 9/100=90ma... i'll prefer to use something like an 1K.

Probably the following post i did few times ago can help. It's a simple frequency counter.
http://www.picbasic.co.uk/forum/showthread.php?t=1044


Cool thanks, i noticed you simply used a 1k on the in and a 10k to ground?

basically i'm using a 6v peak to peak 60hz signal just need zero crossing

[mister_e]

that's different, so you don't need any timer stuff. Just poll the pin or use Interrupt on X pin on rising or falling edge.

The following is another one wich can be handy.
http://www.picbasic.co.uk/forum/showpost.php?p=4763&postcount=5

OR on Melabs website wich also include the schematic. Dimmer.Zip
http://www.melabs.com/resources/samples.htm#submitted

*** EDIT ***
Yeah on the previous i lace 10K to ground to avoid weird reading when the input is left open. That way it ensure the PIC see 0V so never count and display XYZ results.

[chrispol]

Ok that one's using rectified ac not a problem thats where i was gonna grab my 6v, r1 is not listed but will drop in a 1k, i noticed there were no snubbers on the triac but that was for a resistive load here's what i was thinking

http://www.chrisncarol.com/switch.jpg


that's different, so you don't need any timer stuff. Just poll the pin or use Interrupt on X pin on rising or falling edge.

The following is another one wich can be handy.
http://www.picbasic.co.uk/forum/showpost.php?p=4763&postcount=5

OR on Melabs website wich also include the schematic. Dimmer.Zip
http://www.melabs.com/resources/samples.htm#submitted

*** EDIT ***
Yeah on the previous i lace 10K to ground to avoid weird reading when the input is left open. That way it ensure the PIC see 0V so never count and display XYZ results.

[mister_e]

Yup even if the snubber method is recommend, ST do some Snubberness one. I actually test them running few 10 AMP inductive load without any snubber. As now, since 2 weeks, no problem, no fire, no temperature raising seems quite stable... as now

Look the datasheet
http://www.st.com/stonline/books/pdf/docs/7470.pdf

Anybody else here already tried and got success with those St Snubberness BTA/BTB series without snubber??

[M. Tayem]

Hello Steve,

Yes, I am using thousands of ST Snubberless Triacs in Traffic control systems, they drive 230/10 volt transformers for halogen lamps up to 5 amps, they are running 24 hours, continuous switching for about 5 years till now, the maintenance records don't show more than 5 Triacs faults in more than 150 traffic controller each has (30-60) Triac.

Regards
Mohammed

[mister_e]

thanks Mohammed for your reply. Glad to know they work As Is without any extra stuff.