Fluid presence and qualitative measurements by transient immitivity response

An apparatus for obtaining a transient immitivity response for a fluid, comprising:

• a first electrode and a second electrode, the first and second electrodes being spaced apart from each other and both in contact with the fluid;
• an excitation source providing a time varying excitation voltage to the first electrode, the excitation voltage being switched between a first defined voltage level and a distinct second defined voltage level, the first and second voltage levels being alternately applied to the first electrode for specific time periods;
• a capacitance located between the second electrode and an electrical or circuit ground, the ground having a defined ground voltage;
• a detecting means capable of detecting an electrical charge conducted through the fluid as a consequence of the excitation voltage applied to the first electrode, wherein the detecting means has a high input resistance to minimize external current flows;
• and
• a determining means capable of determining one or more rates of change in the electrical charge per time interval, such one or more rates representing the transient immitivity response of the fluid, the determining means capable of providing the transient immitivity response as a digital or analog output.

A method for obtaining a transient immitivity response, comprising the steps of:

• a) contacting a fluid with a first electrode and a second electrode, the first and second electrodes spaced apart from each other;
• b) applying an excitation voltage to the first electrode and switching the excitation voltage between a first defined voltage level and a distinct second defined voltage level;
• c) providing a capacitance between the second electrode and an electrical or circuit ground, the ground having a defined ground voltage;
• d) detecting a sensed voltage resulting from the excitation voltage applied to the first electrode by means of a series resistance;
• e) determining one or more rates of change in the sensed voltage per time interval, such rate or rates representing the transient immitivity response of the fluid;
• and
• f) providing the measured rate or rates representing the transient immitivity response as a digital or analog output.

A method for obtaining a transient immitivity response, comprising the steps of:

• a) contacting a fluid with a first and a second electrode, the first and second electrode being spaced apart from each other;
• b) providing a time varying excitation voltage to the first electrode, the excitation voltage being switched between a first defined voltage level and a distinct second defined voltage level, the first and second defined voltage levels being alternately applied to the first electrode for specific time periods;
• c) providing a capacitance in contact between the second electrode and an electrical or circuit ground, the ground having a defined ground voltage;
• d) detecting a sensed voltage as a consequence of the excitation voltage applied to the first electrode, wherein the detecting step is carried out with a high input resistance to minimize external current flows;
• e) determining a rate or rates of the change in the sensed voltage per time interval or intervals, such rates representing the transient immitivity response of the fluid;
• and
• f) providing the transient immitivity response of the fluid as a digital or analog output.

A method for differentiating between fluids having different dielectric constants, comprising the steps of:

• a) contacting a fluid with a first and a second electrode, the first and second electrode being spaced apart from each other;
• b) providing a time varying excitation voltage to the first electrode, the excitation voltage being switched between a first defined voltage level and a distinct second defined voltage level, the first and second defined voltage levels being alternately applied to the first electrode for specific time periods;
• c) providing a capacitance in contact between the second electrode and an electrical or circuit ground, the ground having a defined ground voltage;
• d) detecting a sensed voltage proportional to electrical charges conducted through the fluid from the first electrode to the second electrode due to the excitation voltage applied to the first electrode, wherein the detecting step is carried out with a high input resistance to minimize external current flows;
• e) repeating steps a-d) so that two or more transient immitivity response measurements are obtained, wherein each measurement is determined using a different value of series resistance applied to the excitation voltages;
• and
• f) providing rates of change in transient immitivity responses between the two or more measurements as a digital or analog output.

A method for measuring transient immitivity response, comprising the steps of:

• a) contacting a fluid with a first and a second electrode, the first and second electrode being spaced apart from each other;
• b) providing a time varying excitation voltage to the first electrode, the excitation voltage being switched between a first defined voltage level and a distinct second defined voltage level, the first and second defined voltage levels being alternately applied to the first electrode for specific time periods;
• c) providing a variable resistance between the excitation voltage and the first electrode, the resistance responsive to temperature changes in the fluid;
• d) providing a capacitance in contact between the second electrode and an electrical or circuit ground, the ground having a defined ground voltage;
• e) detecting a sensed voltage proportional to electrical charges conducted through the fluid from the first electrode to the second electrode as a consequence of the excitation voltage applied to the first electrode, wherein the detecting step is carried out with a high input resistance to minimize external current flows;
• f) determining at least one rate of change in sensed voltage per time interval, such at least one rate representing the transient immitivity response of the fluid;
• and
• g) providing the transient immitivity response as a digital or analog output.