Spectrophotometer
Holmarc's Spectrophotometer (Model No: HOED- TH-01) is ideal for education, research and industrial applications. Unlike other entry level spectrophotometers, it employs the classic Czerny - Turner monochromator design, which ensures low stray light. It uses 1200 lines/mm blazed holographic grating as the dispersion element providing high wavelength resolution. It also employs a sigma delta ADC of 16 bit resolution for photometric measurements. A graphic LCD screen is used to plot an absorbance v/s wavelength graph. The data can then be analyzed for peaks and valleys.
The spectrophotometer can measure the amount of absorbance or lack of absorbance of different colored light for a given molecule. The absorbance spectrum is a graph of a sample's absorbance at different wavelengths.
In a spectrophotometer, the amount of light passing through the sample cell is measured by a photometer. The photometer delivers a voltage signal to a processing unit. The signal changes as the amount of light absorbed by the liquid changes. According to Beer's law, the amount of light absorbed by a medium is proportional to the concentration of the absorbing material or solute present. Thus the concentration of a colored solute in a solution can be determined in the lab by measuring the absorbance of light at a given wavelength.
Experiment:
To study the absorbance and transmittance of different samples at different wavelengths
To plot the graph of absorbance Vs. wave length
Specifications:
| Wavelength | |
| Range | 380 - 1100 nm |
| Resolution | 1 nm |
| Accuracy | ± 1 nm |
| Bandwidth | 2 nm |
| Concentration | |
| Range | 0 to 999 |
| Selectable resolution | 1,0.1,0.01 or 0.001 |
| Readout | 320 x 240 Pixels graphics LCD |
| PC Interface | RS232 (optional) |
| Light source | Tungsten halogen lamp 20 W |
| Transmittance | |
| Range | 0 to 100 % |
| Resolution | 0.1 % |
| Accuracy | ± 1 % |
| Noise levels | < 1 % |
| Stability | ± 1% / Hr after warm-up |
| Absorbance | |
| Range | 0 to 2 A |
| Resolution | 0.001 A |
Features:
| Compact and easy to use |
| LCD display is large enough to read from any distance |
| Selectable resolutions |
Schematic:
