Apparatus for determining the electric properties of a sample

• US 20060114006A1
• Filed: 10/20/2005
• Published: 06/01/2006
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: Moustafa Mohamed
• Original Assignee: Moustafa Mohamed
• Inventors: Mohamed, Moustafa
• Granted Patent: US 7,777,504 B2
• Time in Patent Office: Days
• US Class Current: 324/690
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 33/246 for water content

Abstract

An apparatus for determining the electric properties of a sample. The apparatus comprises a probe having an input, an output, and an effective resistance, inductance and/or capacitance dependent upon the properties of the sample; a pulse generator for producing pulses connected to the input of the probe, each pulse having a period of a sufficient duration to allow the probe to reach steady state; and a measuring device connected to the output of the probe and configured to output a representation of the sample properties based on the effective resistance, inductance and/or capacitance of the probe.

Claims

1. An apparatus for determining the electrical properties of a sample, the apparatus comprising:

a probe having an input, an output, and an effective capacitance that is dependent upon the properties of the sample;

a pulse generator for producing pulses connected to the input of the probe, each pulse having a period of a sufficient duration to allow the probe to reach steady state; and

a measuring device connected to the output of the probe and configured to output a representation of the properties of the sample based on the effective capacitance of the probe.

2. The apparatus of claim 1, wherein the probe also has an effective resistance, and the measuring device is configured to output the properties of the sample based on the effective capacitance and the effective resistance of the probe.

3. The apparatus of claim 2, wherein the properties of the sample are selected from a group consisting of the moisture content, salinity, resistance, inductance and capacitance.

4. The apparatus of claim 2, wherein the measuring device comprises a capacitive element that acts as a simple integrator such that the steady state value of the voltage depends on the effective resistance.

5. The apparatus of claim 2, wherein measuring device comprises a diode or a semiconductor switch connected in series with a capacitive element that acts as an integrator during the discharge cycle, such that the steady state value of the capacitive element depends on the effective capacitance and effective resistance.

6. The apparatus of claim 1, wherein the measuring device comprises a microprocessor.

7. The apparatus of claim 1 wherein the probe comprises two conductors spaced apart at a known distance, the conductors coated by an electrically insulative material.

8. The apparatus of claim 7 used to determine the moisture of a sample independent of the salinity.

9. The apparatus of claim 2 wherein the probe is formed of two conductors spaced apart at a known distance.

10. The apparatus of claim 2 comprising plural probes, wherein the probes are formed of two conductors spaced apart at a known distance and the conductors of at least one probe are coated by an electrically insulative material and the conductors of at least one probe are not coated by electrically insulative material.

11. The apparatus of claim 1 wherein the pulse has a square leading edge.

12. A method for determining the properties of a sample, the method comprising the steps of:

inserting a probe into the sample, the probe having an effective capacitance dependent upon the properties of the sample, the probe having an input and an output;

generating a pulse at the input of the probe having a period of a sufficient duration to allow the probe to reach steady state; and

connecting a measuring device to the output of the probe, the measuring device configured to output a representation of the properties of the sample based on the effective capacitance of the probe.

13. The method of claim 12, wherein the probe also has an effective resistance, and the measuring device is configured to output the properties of the sample based on the effective capacitance and the effective resistance of the probe.

14. The method of claim 13, wherein the properties of the sample are selected from a group consisting of the moisture content, salinity, resistance, inductance, and capacitance.

15. The method of claim 13, wherein the measuring device comprises a capacitive element that acts as an integrator, such that the steady state value of the capacitive element depends on the effective resistance.

16. The method of claim 13, wherein measuring device comprises a diode connected in series with a capacitive element, such that the capacitive element acts as an integrator during the discharge cycle, such that the steady state voltage of the capacitive element depends on the effective capacitance and effective resistance.

17. The method of claim 12, wherein the measuring device comprises a microprocessor.

18. The method of claim 12 wherein the probe comprises two conductors spaced apart at a known distance, the conductors coated by an electrically insulative material.

19. The method of claim 18 wherein used to determine the moisture of a sample independent of the salinity.

20. The method of claim 13 wherein the probe is formed of two conductors spaced apart at a known distance.

21. The method of claim 13 wherein inserting a probe in to the sample comprises inserting plural probes into the sample, wherein the plural probes are formed of two conductors spaced apart at a known distance and the conductors of at least one probe are coated by an electrically insulative material and the conductors of at least one probe are not coated by electrically insulative material.

22. The method of claim 12 wherein generating a pulse comprises generating a pulse with a square leading edge.