Hello All

I am new to programming the Pic. Pic 16c84.
I have wrote a program that requires a pulse when mains is at zero.
I have used a small circuit using a comparator which does the job
but I have read a posting on here about using a 5 meg resistor
connected to the input from the mains to detect zero crossing.

My questions are :-

1) Is 5 meg ok with 240v

2) Do I connect the Ov rail of cct to Neutral or will Earth be ok.

3) I gather I just test bit for being clear for zero crossing.

In case anyone is interested the circuit is for a surge system
for a fish tank. It turns on a pump for 30 secs (soft start)
then turns it off and turns on another pump for 30 secs.
So the zero crossing is required for the soft start.

I know this program probably sounds simple to most of you but
it was my first attempt at programming and I am quite proud of it.

Thanks in advance for any replies to my questions.

Cheers

Ste