>
> 1) That's not a dumb question - you can have lots of fun with mains failure
> when you bring the neutral close to the "ground".

I thought so.

>
> 2) Provided your circuit operates from the live and neutral ONLY, you may
> attach the neutral to the 0V (ground) - unless of course some dumb idiot
> wire the power to you with the live and neutral swapped - do first check that.

Yup that is definitely a possibility. I was planning to drive this circuit
with a wall wart. But it's easy enough to build a quick 5V supply. But the
same issue are still there. Presuming I'm using an integrated bridge rectifier
does it matter which leg of the secondary is connected to ground and which
leg is connected to the input pin?

BAJ