All this talk of bulky transformers and direct line connection to the
PIC makes many people nervous.  Perhaps a small optoisolator to
facilitate zero detection, and a triac to 'fire' your lights ?

pjc

>----------
>From:  Byron A Jeff[SMTP:byron@CC.GATECH.EDU]
>Sent:  Friday, December 06, 1996 12:26PM
>To:    Multiple recipients of list PICLIST
>Subject:       Re: Dumb question on Application Note 521
>
>>
>> PMFJI, I have not seen Appl. Note 521, but a transformer is considered to
>>be a
>> separately derived voltage source by the National Electrical Code(N.E.C.)
>> and the voltage
>> across the secondary windings is of course ungrounded unless you connect
>>one
> of
>> the windings to ground.
>
>App Note 521 specifically talks about wiring the 115V directly to the PIC
>without the use of an isolation transformer. After reading here I've decided
>that it's a bad idea and I plan to use a transformer.
>
>> I hope this helps.
>
>It really does. I'll go ahead and step the voltage down to 9VAC and detect
>the
>zero crossings from there.
>
>BAJ
>