NL7802100A - Measurement of moisture content of substance with capacitative sensor - incorporates parallel oscillator circuit with built in compensation for temp. and conductivity variations - Google Patents

Measurement of moisture content of substance with capacitative sensor - incorporates parallel oscillator circuit with built in compensation for temp. and conductivity variations

Info

Publication number
NL7802100A
NL7802100A NL7802100A NL7802100A NL7802100A NL 7802100 A NL7802100 A NL 7802100A NL 7802100 A NL7802100 A NL 7802100A NL 7802100 A NL7802100 A NL 7802100A NL 7802100 A NL7802100 A NL 7802100A
Authority
NL
Netherlands
Prior art keywords
circuit
moisture content
substance
sensor
pole
Prior art date
Application number
NL7802100A
Other languages
Dutch (nl)
Other versions
NL173099B (en
NL173099C (en
Original Assignee
Stichting Tech En Fysische Die
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Stichting Tech En Fysische Die filed Critical Stichting Tech En Fysische Die
Priority to NL7802100A priority Critical patent/NL173099C/en
Publication of NL7802100A publication Critical patent/NL7802100A/en
Publication of NL173099B publication Critical patent/NL173099B/en
Application granted granted Critical
Publication of NL173099C publication Critical patent/NL173099C/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity
    • G01N27/225—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity by using hygroscopic materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials
    • G01N33/246—Earth materials for water content

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Remote Sensing (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

The moisture content of a material or substance, in particular, soil, is measured by means of a circuit which determines the capacity of a capacitative sensor comprising two electrodes in contact with the soil. The measuring circuit incorporates an LC-oscillator and the sensor is connected parallel to the LC circuit. The LC circuit works together with a voltage dependent resistance element such that a reduction of the value of the resistance across the electrodes is compensated by an increase in the value of the resistance element and vice versa. The voltage dependent element is pref. a Zener diode in series with a diode. The oscillator pref. includes a transistor with ground base, the collector connected via the parallel LC circuit with the input pole of the voltage source and emitter connected via a feedback coil to the second pole of the input voltage source whilst the sensor electrodes are connected to the second pole of the source and with the end of the LV circuit connected to the collector respectively. The measuring circuit enables the moisture content of the material to be measured in terms of the variation of the oscillator frequency whilst eliminating the error due to variations in the conductivity of the sample.
NL7802100A 1978-02-24 1978-02-24 DEVICE FOR DETERMINING THE MOISTURE CONTENT OF A MATERIAL OR SUBSTANCE, IN PARTICULAR SOIL. NL173099C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
NL7802100A NL173099C (en) 1978-02-24 1978-02-24 DEVICE FOR DETERMINING THE MOISTURE CONTENT OF A MATERIAL OR SUBSTANCE, IN PARTICULAR SOIL.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7802100A NL173099C (en) 1978-02-24 1978-02-24 DEVICE FOR DETERMINING THE MOISTURE CONTENT OF A MATERIAL OR SUBSTANCE, IN PARTICULAR SOIL.

Publications (3)

Publication Number Publication Date
NL7802100A true NL7802100A (en) 1979-08-28
NL173099B NL173099B (en) 1983-07-01
NL173099C NL173099C (en) 1983-12-01

Family

ID=19830393

Family Applications (1)

Application Number Title Priority Date Filing Date
NL7802100A NL173099C (en) 1978-02-24 1978-02-24 DEVICE FOR DETERMINING THE MOISTURE CONTENT OF A MATERIAL OR SUBSTANCE, IN PARTICULAR SOIL.

Country Status (1)

Country Link
NL (1) NL173099C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0392639A2 (en) * 1989-04-13 1990-10-17 Rockwool/ Grodan B.V. Method and device for measuring the moisture content of a substrate for growing
CN101520426B (en) * 2008-02-28 2012-05-09 河南农业大学 Measuring method for soil moisture and electrical conductivity based on vectorial resultant and device thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8503554A (en) * 1985-12-23 1987-07-16 Stichting Tech En Fysische Die METHOD AND APPARATUS FOR MEASURING THE MOISTURE VOLTAGE OF A SUBSTRATE

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0392639A2 (en) * 1989-04-13 1990-10-17 Rockwool/ Grodan B.V. Method and device for measuring the moisture content of a substrate for growing
EP0392639A3 (en) * 1989-04-13 1991-04-03 Rockwool/ Grodan B.V. Method and device for measuring the moisture content of a substrate for growing
CN101520426B (en) * 2008-02-28 2012-05-09 河南农业大学 Measuring method for soil moisture and electrical conductivity based on vectorial resultant and device thereof

Also Published As

Publication number Publication date
NL173099B (en) 1983-07-01
NL173099C (en) 1983-12-01

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Legal Events

Date Code Title Description
A1B A search report has been drawn up
BC A request for examination has been filed
SNR Assignments of patents or rights arising from examined patent applications

Owner name: INSTITUUT VOOR MILIEU- EN AGRITECHNIEK

V4 Lapsed because of reaching the maxim lifetime of a patent

Free format text: 980224