Photoelectric Colorimeters

GAOTek photoelectric colorimeters are used to measure the amount of concentration of a specific substance in the solution. Our instrument uses a photoelectric cell for high detection and its simple function offers a user-friendly use. GAOTek’s photoelectric colorimeters are reliable, high quality, and affordable equipment that provide an accurate detection for easier inspection or monitoring. It is compact, easy to carry and portable to allow the user to work in complex conditions.

A photoelectric colorimeter is commonly used in many applications because of its wide range of measurement, precise at high and low concentrations, requires less than 5 cc. of the test solution, easy to manipulate, offers satisfactory results as an inexpensive meter even when used in yellow solutions, and it reading provide a simple relationship between the concentration of solutions.


A photoelectric colorimeter uses a photoelectric cell, amplifiers, color filters, and a current detector. The colorimeter is a light-sensitive device and uses a specific light filter in a visible range to measure the absorption and transmittance of light passing through a solution. The instrument measures the amount of intensity or concentration of the color that develops in the solution.

·         A colorimeter usually consists three main components: a light source, a cuvette containing the sample solution, and a photocell for detection of light passing through the solution. A colored filter or specific LEDs can be used in the instrument for generating colors and then the output of the colorimeter may be displayed by an analog or digital meter in terms of transmittance or absorbance.

·         A voltage regulator may be applied to the colorimeter for voltage protections. Portability offers the colorimeters a useful on-site test, while larger, bench-top instrument useful for laboratory testing. It is based on two laws, Beer’s law and Lambert’s law, according to which the absorption of light transmitted through the medium is directly proportional to the medium concentration.

·         Beer’s law – It states that when a monochromatic ray of light passing through a color solution, its intensity decreases with respect to the concentration of the solution in which the more color concentration, the lesser the intensity.

·         Lambert’s law – It states that when a monochromatic ray of light passes through a color solution, its intensity decreases with respect to the length of the solution.

In colorimeter, the light emission is indicated with a particular wavelength is placed through to get a monochromatic light, which explores the hue of  light to the measuring gadget. This monochromatic light then passes through the sample solution inside the cuvette then the intensity of light decreases. This investigation the shading contrasted with a current standard. A chip then ascertains the absorbance or percent transmittance. Several sample solutions of concentrations are prepared and test. It is then recorded in the graph as plotted of absorbance, thereby it generates a calibration curve.

Common steps for operating the photoelectric colorimeter:

·         Choose a glass filter, it is recommended to use the glass filter that is a list in the procedure.

·         Fill the cuvette with a solution to about three-fourth and place it in the cuvette slot.

·         Turn on the instrument and allow it heat itself for 4 – 5 minutes.

·         Adjust the optical density to zero.

·         Take the test solution to another cuvette and read the optical density.

·         Take the standard solution to a various concentration and note the down the optical densities.

·         A graph will be plotted when taking the concentration of standard solution over the optical density.

·         It can now be calculated from the graph the concentration of the test solution.


GAOTek photoelectric colorimeters are reliable, accurate, and easy to use to help prevent failure in operations. It's also:

·         Compact and portable: which are suitable for working aloft and complex conditions,

·         Simple user interface and easy to use

·         High and continuous performance

·         Software included for the computer used.

·         Wide range of measurement

·         Multi-color visual display

·         Accurate and precise

·         Light and ambient temperature independent

·         Low battery indication

·         Backlight LCD: reading in dim light conditions

·         Reference values and samples are provided

·         Heat absorption filter

·         PC connect via USB

·         Rechargeable Li-on battery that can last for more than 8 hours of use

·         Absorbance mode photometer

·         Special auto-blanking

·         Improved optics for precise measurement

·         Back LCD: reading in dim light conditions

·         A non-luminous surfaces measurement such as skin, fabric, paper, and paint, can also measure luminous surfaces such as LCDs allowing for relative measurement.

·         Automatic and manual calibration.

·         A relative function which allows comparison between solutions.


Due to the precise accuracy to measure or inspect the substance of the solution. Photoelectric Colorimeters are widely used in various applications such as monitoring the growth rate of yeast or bacterial material, food industry, biochemistry, agriculture and medical industries. It also uses the assess the color of a bird’s plumage. Its major applications are used in the field of chemistry. It is used for lab purposes like measuring the quality of water or different chemicals are tested to fit the qualities.



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