GB1423197A - Photometers - Google Patents
PhotometersInfo
- Publication number
- GB1423197A GB1423197A GB1941173A GB1941173A GB1423197A GB 1423197 A GB1423197 A GB 1423197A GB 1941173 A GB1941173 A GB 1941173A GB 1941173 A GB1941173 A GB 1941173A GB 1423197 A GB1423197 A GB 1423197A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sample
- fine adjustment
- coarse
- channel
- gain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000523 sample Substances 0.000 abstract 7
- 238000010521 absorption reaction Methods 0.000 abstract 2
- 239000012496 blank sample Substances 0.000 abstract 1
- 238000005259 measurement Methods 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
- G01J1/16—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using electric radiation detectors
- G01J1/1626—Arrangements with two photodetectors, the signals of which are compared
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Theoretical Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
1423197 Zero compensation for two path photometers LABTRONIC AG GES FUR KLINISCHE LABORTECHNIK 24 April 1973 [25 April 1972] 19411/73 Heading G1A A photometer for measuring the absorption of a sample by comparison with a reference beam is provided with a zero compensation circuit including an electronic switching arrangement controlling the respective gains of amplifiers in the sample and reference channels to equalize their outputs when a 'blank' sample is used, the arrangement being such that a coarse adjustment followed by a fine adjustment is performed. As shown, Fig. 1, the signals from a sample channel photo-cell 31 and a reference channel photo-cell 34 are passed through respective amplifiers 32, 35 to outputs 45 and 46 to which a ratio circuit is connected to evaluate the absorption of the sample. The gains of amplifiers 32 and 35 are adjustable by means of FETs positioned in feedback paths, the resistance of each FET, and hence the gain of the associated amplifier, being determined by a logic circuit 33 under control of a binary counter (not shown). Fine control of the gain of the reference channel is provided through a D:A converter 39 under control of a binary counter 38. The outputs at terminals 45 and 46 are monitored by a comparator 37. To effect zero setting a blank sample is inserted and key 36 closed. Logic circuit 33 then increases the gain of both channels in coarse steps until the output voltages are suitable for subsequent circuits and the output of the reference channel is slightly below that of the sample channel. The coarse adjustment is then stopped and the fine adjustment is started, a clock 41 feeding counter 38 to increase the reference channel output until it is identical to the sample channel output. The fine adjustment is then stopped and lamp 40 is illuminated to indicate that the zero setting operation is complete. The coarse and fine adjustment counts are stored to maintain the gains of the two channels constant during subsequent measurements.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19722220230 DE2220230C3 (en) | 1972-04-25 | 1972-04-25 | Circuit for automatic zero adjustment for a phonometer for digital display of the light absorption of a measurement sample |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1423197A true GB1423197A (en) | 1976-01-28 |
Family
ID=5843208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1941173A Expired GB1423197A (en) | 1972-04-25 | 1973-04-24 | Photometers |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE2220230C3 (en) |
| GB (1) | GB1423197A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3135443A1 (en) * | 1981-09-08 | 1983-03-24 | Leybold-Heraeus GmbH, 5000 Köln | METHOD AND PHOTOMETRIC ARRANGEMENT FOR THICKNESS MEASUREMENT AND CONTROL OF OPTICALLY EFFECTIVE LAYERS |
| JPS5848832A (en) * | 1981-09-17 | 1983-03-22 | Horiba Ltd | Compensation circuit for analizer |
-
1972
- 1972-04-25 DE DE19722220230 patent/DE2220230C3/en not_active Expired
-
1973
- 1973-04-24 GB GB1941173A patent/GB1423197A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2220230A1 (en) | 1973-11-08 |
| DE2220230C3 (en) | 1975-01-16 |
| DE2220230B2 (en) | 1974-05-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |