Well it's the holiday season and like Tim Allen it's time for me to start
working on my Christmas Lights. I decided this year to soften the chasing
lights scene and to use fading in and out of different strings. While my
Motorola MOC3010 type circuits works fine, for dimming I need to detect
zero crossings. I plan to turn the lights one an off for whole cycles instead
of trying to triggerfor a portion of the cycle which generates that buzzing
sound.

Enter AppNote 521 "Interfacing to AC Power Lines". Conceptually it's simple
but I have to ask the dumb question: What's the return on the AC line? I can't
see how connecting just the hot line of the AC power is going to get you
anywhere and I'm damn scared to connect the neutral up anywhere near the
microcontroller.

Can anyone clarify?

BAJ