LABEC V-11D - Manual (Page 5)

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Shows visible damage
Fails to perform the intended measurements
Has been subjected to prolonged storage under unfavorable conditions
Has been subjected to severe transport stresses
Working Principle:
The spectrophotometer consists of five parts:
1) Halogen or deuterium lamp to supply the light;
2) A Mono-chromator to isolate the wavelength of interest and eliminate the unwanted
second order radiation;
3) A sample compartment to accommodate the sample solution;
4) A detector to receive the transmitted light and convert it to an electrical signal;
5) A digital display to indicate absorbance or transmittance. The block diagram (Fig 1-1)
below illustrates the relationship between these parts.
Block diagram for the Spectrophotometer
Light Mono- Sample Detector Display
Source chromator Compartment
Fig1-1
In your spectrophotometer, light from the lamp is focused on the entrance slit of the
monochromator where the collimating mirror directs the beam onto the grating. The
grating disperses the light beam to produce the spectrum, a portion of which is focused on
the exit slit of the monochromator by a collimating mirror. From here the beam is passed
to a sample compartment through one of the filters, which helps to eliminate unwanted
second order radiation from the diffraction grating. Upon leaving the sample compartment,
the beam is passed to the silicon photodiode detector and causes the detector to produce
an electrical signal that is displayed on the digital display.
100%T
0 Abs