MagneTek makes a really cute 60Hz current sense transformer (part number
CSE187-L). It about the size of and looks like a transistor radio output
transformer. It can handle up to 30 amps with an output of 110mv/amp
into a 60 ohm load resistor.
The best part is that it is that it is available from Digi-Key (PN
237-1103) for only $2.89 (US) in single quantity, $1.60 each in
hundreds!

-- Rich



"R. William Kichman" wrote:
>
> > Maybe this has been covered before, but please bear with me...
> >
> > I need to measure AC current at 60 Hertz, 0 to 35 amps to approx. 0.1A or so
> > precision.  How might I most easily do such measurement using a
> > microcontroller?  I understand that a voltage measurement across a precision
> > resistor, or a few wraps of coated wire around a conductor will allow a
> > current to be calculated, but with AC, isn't the measurement time varying?
> > Won't the A/D read a constantly varying event and get something between 0A
> > and peak current?
> > What am I missing here?
> > Any links to URLs with similar projects would be welcome.
> > Thanks for your time.
> >
> > Bill K.