How to scope the power network?

[Martin Naef]

On 18.04.2012 3:15, Joost Schuttelaar wrote:
> In my new apt there seems to be some weird glitches in the power. I'd
> like to just plot the 50Hz sinewave on my Mac. Anyone have an idea
> how to? Could I just use a 230->12V AC transformer, stick in a ... Ω
> resistor and plug it into my audio in? Or does anyone have a better
> idea? :)

Depends on what exactly you're trying to measure. If you look at short 
interruptions or voltage sag/spikes, the transformer should do fine. But 
keep in mind that a standard transformer will act as a filter on its 
own, so trying to figure out precise harmonics might not be very successful.

I can think of some relatively easy ways to reduce the voltage, but they 
definitely do not fall under the category "safe", which is what it 
should be for 230V mains...

Martin