PASCO OS-8542 BLACK BODY LIGHT SOURCE - Manual (Page 13)

012–07105B Black Body Instruction Manual
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1. Calibrate the Rotary Motion Sensor
Determining the wavelength from the prism spectrophotometer requires and exact measurement of the
angle. To calibrate the rotary motion sensor, determine the ratio of the disk radius to the pin radius
(approximately 60:1) as follows:
a) Remove the prism mount and the light sensor bracket from the degree plate by unscrewing the two
small thumbscrews. Start the DataStudio program and select a rotary motion sensor. Make a
digits display of the angular position, and turn the degree plate so that the zero degree mark is
exactly aligned with the index mark.
b) Start recording data. Slowly and continuously turn the degree plate clockwise for exactly one
complete rotation.
c) Stop recording data. Record the maximum value of the angle. Divide this number by 360 (or 2
π if
it is in radians mode). This is the ratio of the radii. Record this number in the calculator in
DataStudio.
2. Tare the Light Sensor
Note: For best results and to avoid measurement drift, tare the light sensor before scanning
the spectrum and/or before each experiment run. To turn the light source on, click the On
button in DataStudio’s Signal Generator box.
a) Rotate the light sensor arm until it hits the stop against the angle indicator on the spectrophotometer
table.
b) Block the light source by placing your hands between the collimating slits and the collimating lens.
c) While the light is blocked, press the tare button on the light sensor to zero the sensor.
Calibration
A. Scanning a Spectrum
1. Tare the light sensor (as described in the section above).
2. Remove your hand to unblock the light and start recording data (Click the Start button in the
DataStudio setup window) on the computer. Slowly rotate the light sensor arm through the spectrum.
3. To determine the initial angle from the light source, continue to rotate the arm until the light sensor
has passed through the white light that passes under the prism (i.e the degree plate has rotated
pass the zero degree mark).
Procedures