Teledyne 6600 - Manual (Page 67)

Part II: 1-3
Oil in Water Analyzer Operational Theory 1
Teledyne Analytical Instruments
Interconnection Diagram
1.3 Photometer Amplifier
The photo detector converts the photo energy striking it to electrical
energy. The magnitude of the photo energy pulses that strike the detector is
determined by absorbance by the sample and the properties of the optical
filters.
The detector output, which is a sequence of pulses that directly reflect
the photo energy transmitted by the measuring and reference filter, is a
measure of the concentration of the component of interest in the sample. The
difference in energy between the measuring and reference pulse is related
exponentially to the concentration of the component of interest.
The photo detector current output is amplified by a current to voltage (I
to E) converting amplifier, followed by a second amplifier. The gain of the
amplifier can be adjusted to obtain any desired output level.