18
4.
Fluorescent open bulb.
A non-frosted coned fluorescent
bulb exposes the glass tube
completely therefore producing
an oscillating “B” field, which
depends on the number of
tubes.
Accuracy =
0.5% + 2% + 7.9% < +/- 10.4%
5.
Incandescent clear glass.
Old-fashioned incandescent
bulb gives the largest error due
to a non-circular tungsten
thread.
Accuracy =
0.5% + 2% + 10.2% < +/- 12.7%
Based on the above, the average accuracy is then calculated as follows:
Total Average Lumen Error
= spectrometer intensity error + sensor error + (circular field error
type1 + type2 + type3 + type4+ type5) / 5
= 0.5% + 2% + (1.6% + 2.3% + 4.6% + 7.9% + 10.2%) / 5
= < +/- 7.82%
