GENERAL
Colorimeter – the quantitative determination
of colored substance in solutions –
greatly enhances accuracy over visual methods.
This colorimeter is a general-purpose instrument
and simple to operate that can be used for
clinical laboratories, petroleum and agricultural
analysis. It is equally valuable in water
pollution investigation when used with reagents
to detect pollutant.
DESCRIPTION
The instrument essentially comprises of
:-
1. Light source – 6V, 10 W Tungsten
filament lamp.
2. IC – Regulated power supply.
3. Optical system consisting of Reflector
– lens combination.
4. Fixed aperture of incident light.
5. 5/8 glass filters are mounted.
6. Test tube holder for housing test tube
containing solutions.
7. Photodiode for detecting amount of light
passing through the test tube solutions.
8. A 2.5 digit seven segment DISPLAY in
built.
OPERATING PRINCIPLE
The operation of the equipment is primarily
based on the two fundamental laws of light
absorption: -
1. Lambert’s Law – Which states
that the proportion of light absorbed by
an absorbing is independent of the intensity
of the incident light, and
2. Beer’s Law – Which states
that proportion of light absorbed depends
on the total number of absorbing molecules
through which the light passes. Thus, from
these laws, it can be defined that if the
light is passing through a given depth of
solution of an absorbing substance in non
absorbing medium then the proportion of
the light absorbed is dependent upon the
concentration of the absorbing substances.
3. An alternative way to find the concentration
of the test is to take use of previous prepared
graph showing the density of the test on
the colorimeter, corresponding concentration
can be read on the graph.
However, this method can be a serious source
of error unless the graph is frequently
checked by the person actually doing the
analysis.
| SPECIFICATION |
| Wave Length Range |
: 400 – 700 nm |
| Wave Lengths peak at |
: Violet (400), Blue (490), Green (520),
Yellow (590), Red (650) nm
5 Filters
400, 490, 520, 540, 590, 620, 650, 700
nm
8 Filter |
| Minimum Volume |
: 1.0 ml |
| Light Source |
: 6 V, 10 W, Tungsten Filament Lamp |
| Test Tubes |
: 12 mm diameter (Inner) |
| Detector |
: High Sensitive Photodiode |
| Display |
: A 2.5 Digit seven segment display
with special built-in push switch is
given for accurate fast and precise
reading of trans- mission and optical
density. |
| Input Voltage |
: AC Mains : 220 V, 5%, 50 Hz, AC |
| Battery |
: 12 V |
| Ambient Temperature |
: 100 C to 450 C |
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CONTROLS
This instrument consists of following
control knobs and their uses are as
below :-
1. On/Off Switch – This is a 2
position Roker switch given at the side
of the instrument and used to switch
ON the instrument at the time of it
use. It should be switched off when
instrument is not in use.
2. Digital Display – A 2.5 digit
seven segment display with special built
in push switch is given for accurate
fast and precise reading of transmission
and optical density.
3. Cuvette Holder – The cuvette/test
tube holder keeps the test tube containing
samples/standard/blank.
4. ‘O’ Adj. Knob –
Adjust full scale or 100% transmission
on digital display by the help of the
‘COARSE & FINE’ knobs
given at front top of the instrument.
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