Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: pasco light probe oscillations



Thanks to those who offered suggestions as to why I was finding a 15s period
oscillation in the readings from the pasco light probe. Yes, I was using an
ac supply to run the lamp, so it was pulsing at 100 Hz. The interface was
sampling at 20 Hz, but as was suggested the frequencies were not spot on, so
I was getting a slowed down strobed version of the lamp pulsations. At
least, that's how it looks at the moment!

In fact, even if the frequencies were spot on I now realise that it was
pretty stupid to use ac. Using rectified ac with a fat smoothing unit does
eliminate the oscillation, although there's a good deal of noise to be
eliminated

Thanks again, Mark.

Mark Sylvester
United World College of the Adriatic
34013 Duino TS
Italy.
msylvest@spin.it
tel: +39 49 3739 255