US4459995A - Indicating device for use in a device for measuring and indicating changes in resistance of a living body - Google Patents
Indicating device for use in a device for measuring and indicating changes in resistance of a living body Download PDFInfo
- Publication number
- US4459995A US4459995A US06/304,594 US30459481A US4459995A US 4459995 A US4459995 A US 4459995A US 30459481 A US30459481 A US 30459481A US 4459995 A US4459995 A US 4459995A
- Authority
- US
- United States
- Prior art keywords
- resistance
- meter
- transistor
- frame
- indicating
- 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 - Lifetime
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 230000035945 sensitivity Effects 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 238000010276 construction Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
- G01R17/10—AC or DC measuring bridges
Definitions
- This invention relates to the responsiveness of devices for indicating variations in the electrical resistance of the human body.
- Mr. Hubbard's invention while being designed to indicate small changes in resistance of a living body was hampered in that while the circuitry could detect the small changes in resistance, the meter could not accurately track and indicate the changes.
- prior art meters were utilized. Such prior art meters improved their tracking by increasing the torque to moment ratio of the movement by decreasing the mass of the needle and by decreasing the mechanical resistance of the movement suspension. Such improved meters while being better still do not sufficiently and accurately track and indicate the changes. In addition, such meters are undesirable since the meter is critically damped so that the needle does not overshoot the level and the decrease in mass of the needle results in a very fine needle which is difficult to see.
- an electrical resistance measuring or indicating device comprising a bridge network having on one side thereof a first resistance connected to a second resistance arm and on the other side thereof, a first voltage arm connected to a second voltage arm, there being between the junction of the first and second resistance arms and the junction of the first and second arms, a transistorized amplifier circuit and indicating means responsive to changes in balance of the bridge network so as to indicate or measure the resistance, or variations in resistance, of a subject such as a body or part connected to the network across one of said resistance arms.
- a first variable potentiometer means is associated with one of the voltage arms for controlling the range over which the device can operate in the indication of variations in resistance and a second variable potentiometer means is arranged between the junction of the first and second resistance arms and the amplifier circuit, the arrangement being such that when the bridge network becomes unbalanced by the application of a subject thereto, balance can be restored by the adjustment of the first potentiometer means so that the indicating means will respond to very small changes in resistance of said subject.
- the indication of the changes in resistance must be immediately responsive. Therefore a special meter which has is uncritically damped is utilized. The uncritically damped meter is created by providing a meter coil frame which has zero conductivity.
- FIG. 1 is a schematic diagram illustrating the circuit of the device.
- FIG. 2 is a front view of the device.
- FIG. 3 is a perspective view of the frame coil.
- FIG. 4 is a perspective view of the meter movement showing the frame coil in use.
- the D.C. amplifier comprises three transistors Q1, Q2 and Q3 which derive their operating power from the battery B1, the transistors each consisting in the present embodiment of a 2N1303 transistor. It will be noted that in FIG. 1, the input to the D.C. amplifier is applied between the base and emitter of the first transistor Q1, the emitter of Q1 being connected to the battery B1 through a 4.7K resistor R5 and and switch S1. This potential difference is equal to the battery voltage so that the circuit behaves exactly as though it were indeed connected as a simple bridge.
- Transistor Q1 of the input stage is an emitter follower having a fairly high input resistance, it being necessary to keep the input resistance of the amplifier high relatively to the resistance of the bridge in order to prevent loading, since loading is particularly important when the bridge is operated in an unbalanced condition.
- a telephone jack J1 having spring contacts adapted to be connected.
- contact 2 is connected to the slider of the range control potentiometer VR 2 and is also operatively associated with a single pole switch S3 in such a manner that when the plug is withdrawn, switch S3 closes to connect across the jack contacts 1 and 2, a 5K ohm resistor R1 in place of the subject's body.
- the resistance arms R3 and R2 and VR3, of the bridge comprise resistors of 22K ohms, and 3.8K and 2.5K ohms respectively.
- the range control potentiometer VR2 is connected at one end to the negative side of the battery B1 through switch SIA and at the other end to the Tap of battery B1 through 5K ohm resistor VR4 and a switch S1D.
- the base of the transistor Q1 is also connected through resistor RI2 or RI3 or RI4, depending on desired range of sensitivity as selected by S2A, to the negative side of meter M1 and the collector of transistor Q1 is connected through switch S1A to the negative side of battery B1.
- the emitter of Q1 is connected through a 470 ohm resistor R6 to the base of the second state transistor Q2, the latter being arranged as a conventional common-emitter stage which provides most of the current gain.
- the emitter of Q2 is connected through a 5K ohms preset variable resistor VR6 to the positive side of batter B1 and this emitter of Q2 is also connected through a sensitivity control VR5 comprising a 10K ohm reverse-log variable resistor and through the switch S10 to the Tap of battery B1.
- the collector of Q2 is connected directly to the emitter of Q3, and is also connected through a 5.6K ohm resistor R8 and switch S1A to the negative side of battery B1.
- the base of Q3 is connected to the junction of resistors R10 and R11, each of 22K ohms, R10 being connected through switch S1A to the negative side of battery B1 and the other end of R11 being connected to the slider of resistor VR5.
- the collector of Q3 is connected to a switch S1C so that by operation of the switch S1C the collector can be connected to the positive side of the meter.
- the meter is shunted by a 5.6K ohm resistor R16 and a 5K variable resistor VR7 in series, and the negative side thereof is connected through a 22K ohm resistor R15 and switches S1B and S1A to the negative side of the battery B1.
- the switch S1C and S1A and S1B when S1 is in the 3rd position, respectively connects the positive side of the meter M1 to the positive side of B1 and connects the negative side of the meter M1 to the negative side of B1 via a 90K ohm resistor R19. With S1 in the 3rd position the meter is shunted by a 5K ohms variable resistor VR8.
- the transistor Q3 of the output stage is connected in the common-base configuration and constitutes an impedance matching device feeding the indicating meter M1.
- the resistors R12, R13 and R14 are negative feedback resistors which determine the overall gain. Their value depends upon the position of S2A.
- Switch S2 is a double pole treble throw. In position one, a 470K ohm resistor R12 is connected as the feedback resistor. In position 2, a mega ohm resistor R13 is connected as the feedback resistor. In position 3, two one mega ohm resistors R13 and R14 are connected in series as the feedback resistors.
- a variable opposite potential is applied to the base of Q1 using switch S2B.
- a 200K ohm resistor R4 and a 75K ohm resistor R21 is connected between the base of Q1 and the negative side of B1.
- a 200K ohm resistor R4 is connected between the base of Q and the negative side of B1.
- Switch S1A, B, C, D, E, F is a 5 pole treble throw switch operated by knob B' (FIG. 2).
- the indicating meter M1 is a moving-coil meter capable of reading from 0 to 100 microamps at full scale deflection, the meter having an arcuate scale H' (FIG. 2) divided into sections.
- the meter M1 is designed to be undamped and therefore accurately tracks the changes in resistance of the living body and constitutes another improvement since it too improves the sensitivity of the device.
- the construction of the improved meter M1 will be described later below.
- At about one-third scale deflection there is provided a small sector of the arc marked "SET”.
- TEST At the full-scale end of the arc there is another small section marked "TEST". Between these two small sectors, the scale is marked "FALL".
- the 5K ohm preset variable resistor VR1 is provided between the subject terminals and the amplifier detector, to permit compensation for variations in component values.
- the resistance value of the optimum female subject is 5K ohms and the instrument is therefore standardized at this value.
- a control C' (FIG. 2) marked "TRIM”.
- the range control potentiometer VR2 has a control knob FE' and a linear scale I' marked from “1" to "6" and extending over an arc of 240°, which is divided into divisions of 48°.
- VR1 is adjusted in such manner that when the input jack plug is withdrawn, and the 5K ohm resistor R1 is thus connected across the input, a balance is established when the range control VR2 is set to "2" on its scale.
- the balance point should be at "3" on the range control scale I' of VR2 with a resistance of 12,500 ohms connected across the input.
- the meter pointer G' should indicate the center of "SET” sector of the scale when the control E' of VR2 is set to read “2" on its scale.
- the control E' In order to set up the calibration it is a merely necessary to set the control E' to "2", withdraw the plug of the jack J1 and adjust VR1 by means of the control C' to bring the meter pointer to the correct deflection.
- the gain of the amplifier is adjusted by means of a knob D' (FIG. 2) of the sensitivity control VR5 which varies the negative feedback applied to transistor Q2, part of the emitter current of Q2 flowing through VR5 and part through the pre-set variable resistor VR6.
- the latter is adjusted to such a value that, when the meter pointer is at the center of the "SET" sector of the scale, the voltage drop across is just equal to the battery voltage; thus, for this reading and for this reading only, no current flows in VR5 and its setting does not affect the indication of the meter.
- transistor Q1 is an emitter follower whose output is delivered to the base of transistor Q2 through resistor R6.
- the emitter of Q2 receives bias voltage at the junction of resistors VR6 and VR5, adjusted by means of VR5.
- the base of transistor Q3 receives bias voltage at the junction of resistors R10 and R11.
- the output current of the amplifier flows from the collector Q3 through the indicating meter M1 with compensation for voltage drift provided by the interconnection of the collector Q2 and the emitter of Q3, as above described.
- the first stage of the amplifier is an emitter follower and the second and third stages are cascaded in a manner to provide drift compensation, as above described.
- Switching S1 to position 3 also connects a half wave rectifier, charging unit, powered at J2 by the 115 volts A.C.
- the rectifier consists of Diodes D1 and D2 that allow only one direction of the A.C. current to pass.
- a slow blow fuse F1 is to protect the device in case of high voltage surges.
- Resistor R17 of 27 ohms protects the batteries from high voltage surges.
- a capacitor of 0.68 microfarads C1 determines the speed of charging.
- R18 of 470K ohms drains C1 of charge when the unit is not charging. This is an improvement as nickle cadmium batteries can now be recharged when in the device, where in the original device the batteries had to often be replaced.
- the meter movement used in the device for measuring and indicating changes in resistance of a living body is 1450 ohm wire coil C wound on a circular metal frame A.
- the improvement is based on the inductance of the circular metal frame A absorbing a significant amount of any sudden change of current in the coil C.
- the absorbed energy is lost in setting up a current in the metal frame A, at the Frame A is an inductor of negligable resistance. Thus there is significantly less energy available to deflect the needle G.
- the device comprises a metal frame A, shaped to hold a wire wound coil C, with a split at point B, to reduce the conductivity of the frame A to zero, thus preventing energy loss in the form of current inducted magnetically into the frame A.
- a 1450 ohm, wire wound coil C one end of which is electrically connected to point D which is used both as one of the electrical connections for coil C and one of the pivots for frame A and needle G.
- the other end of coil C is electrically connected to point E which is used for both the electrical connection for coil C and the other pivot for frame A and needle G.
- Needle G is physically connected to frame A, and is the indicator of the device for measuring the indicating changes in resistance of a living body.
- Counter weight H is used to balance needle G at the point needle G is connected to frame A.
- An iron cylinder F is provided within and is pivotally coupled to the frame A and therefore remains motionless. The iron cylinder F further serves to concentrate the magnetism on which the device operates.
- a stationary housing is used (but not shown) to connect the movement electrically, magnetically and physically to the device for measuring and indicating changes in resistance of a living body.
- a wire wound coil C could be used with no frame A at all, by making the coil C stiff with varnish (a nonconductor).
- the end product is very similar, i.e. a coil without extra inductance and therefore current flow, in the frame A, and it has demonstrated similar results.
- a structure requires delicate construction techniques and is not as rugged as a meter with a split frame A.
Abstract
Description
TABLE ______________________________________ Input Original Device With split frame ______________________________________ 0.1 to .001 second, not visible or very visible high energy pulse barely visible .2 to .01 second, Visible after a .2 to visible after a .02 to high energy pulse .5 second lag. Amount .05 second lag. Amount of deflection noticably of deflection not reduced by inductance measurable reduced absorption of pulse. by absorption of pulse. .2 to .01 second, Invisible or Clearly visible low energy pulse nearly so. Sudden change to new Moves sluggishly after Moves sharply to new current flow level .2 to .5 second lag to level after only .02 new level. to .05 second lag ______________________________________
Claims (6)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/304,594 US4459995A (en) | 1979-03-08 | 1981-09-22 | Indicating device for use in a device for measuring and indicating changes in resistance of a living body |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US1872779A | 1979-03-08 | 1979-03-08 | |
US06/304,594 US4459995A (en) | 1979-03-08 | 1981-09-22 | Indicating device for use in a device for measuring and indicating changes in resistance of a living body |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US1872779A Continuation-In-Part | 1979-03-08 | 1979-03-08 |
Publications (1)
Publication Number | Publication Date |
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US4459995A true US4459995A (en) | 1984-07-17 |
Family
ID=26691424
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/304,594 Expired - Lifetime US4459995A (en) | 1979-03-08 | 1981-09-22 | Indicating device for use in a device for measuring and indicating changes in resistance of a living body |
Country Status (1)
Country | Link |
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US (1) | US4459995A (en) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4578635A (en) * | 1981-01-14 | 1986-03-25 | Mee John L | Device for measuring and indicating changes in the resistance of a living body |
US4690152A (en) * | 1985-10-23 | 1987-09-01 | American Mediscan, Inc. | Apparatus for epithelial tissue impedance measurements |
US4702259A (en) * | 1985-09-06 | 1987-10-27 | Author's Family Trust | Device for measuring and indicating changes in resistance of a living body |
US4729385A (en) * | 1985-10-23 | 1988-03-08 | American Mediscan, Inc. | Probe and method of use for detecting abnormal tissues |
US4770186A (en) * | 1985-03-20 | 1988-09-13 | Zetek, Inc. | Method and apparatus for predicting and detecting the onset of ovulation |
US4812126A (en) * | 1985-05-28 | 1989-03-14 | Byron Gilliksen | Education or learning aid method |
US4864282A (en) * | 1986-10-21 | 1989-09-05 | Sasson Toeg | Method and apparatus for detecting or measuring the presence of humans or biological organism |
US4895163A (en) * | 1988-05-24 | 1990-01-23 | Bio Analogics, Inc. | System for body impedance data acquisition |
US4899750A (en) * | 1988-04-19 | 1990-02-13 | Siemens-Pacesetter, Inc. | Lead impedance scanning system for pacemakers |
US4926880A (en) * | 1988-11-08 | 1990-05-22 | Microcurrents | Method for relieving sinus and nasal congestion utilizing microcurrents |
WO1997041774A1 (en) | 1996-05-09 | 1997-11-13 | Church Of Spiritual Technology | A system for measuring and indicating changes in the resistance of a living body |
US6564079B1 (en) | 2000-07-27 | 2003-05-13 | Ckm Diagnostics, Inc. | Electrode array and skin attachment system for noninvasive nerve location and imaging device |
US20080139957A1 (en) * | 2003-03-19 | 2008-06-12 | Church Of Spiritual Technology, Inc. | System For Measuring And Indicating Changes In The Resistance Of A Living Body |
US20150293045A1 (en) * | 2014-04-11 | 2015-10-15 | Texas Instruments Incorporated | Measuring electrode impedance in an impedance measurement circuit |
US10006950B2 (en) | 2014-04-24 | 2018-06-26 | Texas Instruments Incorporated | Impedance measurement circuit |
US10739433B2 (en) | 2016-03-21 | 2020-08-11 | Texas Instruments Incorporated | Calibrating body impedance measurement systems |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
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US2827041A (en) * | 1954-05-10 | 1958-03-18 | William B Pierson | Electrical testing and treatment apparatus |
US2949591A (en) * | 1955-10-10 | 1960-08-16 | United Transformer Corp | Miniature inductive devices |
US3290589A (en) * | 1965-06-07 | 1966-12-06 | Lafayette R Hubbard | Device for measuring and indicating changes in resistance of a living body |
US3452743A (en) * | 1965-03-01 | 1969-07-01 | Gen Electric | Body impedance bridge |
US3468302A (en) * | 1966-05-20 | 1969-09-23 | Godfrey Brooke | Skin resistance reaction time testing apparatus |
US3772593A (en) * | 1971-11-03 | 1973-11-13 | P Sidhu | Resistance measurement system |
US3841316A (en) * | 1973-02-26 | 1974-10-15 | Owens Illinois Inc | Apparatus for measuring the psychogalvanic reflex |
US4016870A (en) * | 1975-10-14 | 1977-04-12 | Chuck Lock | Electronic acupuncture point finder |
US4024472A (en) * | 1974-08-02 | 1977-05-17 | Weston Instruments, Inc. | Meter construction |
-
1981
- 1981-09-22 US US06/304,594 patent/US4459995A/en not_active Expired - Lifetime
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2827041A (en) * | 1954-05-10 | 1958-03-18 | William B Pierson | Electrical testing and treatment apparatus |
US2949591A (en) * | 1955-10-10 | 1960-08-16 | United Transformer Corp | Miniature inductive devices |
US3452743A (en) * | 1965-03-01 | 1969-07-01 | Gen Electric | Body impedance bridge |
US3290589A (en) * | 1965-06-07 | 1966-12-06 | Lafayette R Hubbard | Device for measuring and indicating changes in resistance of a living body |
US3468302A (en) * | 1966-05-20 | 1969-09-23 | Godfrey Brooke | Skin resistance reaction time testing apparatus |
US3772593A (en) * | 1971-11-03 | 1973-11-13 | P Sidhu | Resistance measurement system |
US3841316A (en) * | 1973-02-26 | 1974-10-15 | Owens Illinois Inc | Apparatus for measuring the psychogalvanic reflex |
US4024472A (en) * | 1974-08-02 | 1977-05-17 | Weston Instruments, Inc. | Meter construction |
US4016870A (en) * | 1975-10-14 | 1977-04-12 | Chuck Lock | Electronic acupuncture point finder |
Cited By (25)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4578635A (en) * | 1981-01-14 | 1986-03-25 | Mee John L | Device for measuring and indicating changes in the resistance of a living body |
US4770186A (en) * | 1985-03-20 | 1988-09-13 | Zetek, Inc. | Method and apparatus for predicting and detecting the onset of ovulation |
US4812126A (en) * | 1985-05-28 | 1989-03-14 | Byron Gilliksen | Education or learning aid method |
US4702259A (en) * | 1985-09-06 | 1987-10-27 | Author's Family Trust | Device for measuring and indicating changes in resistance of a living body |
US4690152A (en) * | 1985-10-23 | 1987-09-01 | American Mediscan, Inc. | Apparatus for epithelial tissue impedance measurements |
US4729385A (en) * | 1985-10-23 | 1988-03-08 | American Mediscan, Inc. | Probe and method of use for detecting abnormal tissues |
NL8702072A (en) * | 1986-09-04 | 1988-04-05 | Authors Family Trust | DEVICE FOR MEASURING AND INDICATING CHANGES IN RESISTANCE OF A LIVE BODY. |
AU612984B2 (en) * | 1986-09-04 | 1991-07-25 | Church Of Spiritual Technology | Device for measuring and indicating changes in resistance of a living body |
DE3729321A1 (en) * | 1986-09-04 | 1988-03-31 | Authors Family Trust | DEVICE FOR MEASURING AND DISPLAYING RESISTANCE CHANGES IN A LIVING BODY |
FR2603700A1 (en) * | 1986-09-04 | 1988-03-11 | Authors Family Trust | DEVICE FOR MEASURING AND INDICATING VARIATIONS IN RESISTANCE OF A LIVING BODY |
US4864282A (en) * | 1986-10-21 | 1989-09-05 | Sasson Toeg | Method and apparatus for detecting or measuring the presence of humans or biological organism |
US4899750A (en) * | 1988-04-19 | 1990-02-13 | Siemens-Pacesetter, Inc. | Lead impedance scanning system for pacemakers |
US4895163A (en) * | 1988-05-24 | 1990-01-23 | Bio Analogics, Inc. | System for body impedance data acquisition |
US4926880A (en) * | 1988-11-08 | 1990-05-22 | Microcurrents | Method for relieving sinus and nasal congestion utilizing microcurrents |
WO1997041774A1 (en) | 1996-05-09 | 1997-11-13 | Church Of Spiritual Technology | A system for measuring and indicating changes in the resistance of a living body |
US6011992A (en) * | 1996-05-09 | 2000-01-04 | Church Of Spirtual Technology | System for measuring and indicating changes in the resistance of a living body |
AU724109B2 (en) * | 1996-05-09 | 2000-09-14 | Church Of Spiritual Technology | A method and device for measuring and indicating changes in the resistance of a living body |
CZ296779B6 (en) * | 1996-05-09 | 2006-06-14 | Church Of Spiritual Technology | Method for maintaining generally constant amplitude response to a given measured input and a device making the same |
US6564079B1 (en) | 2000-07-27 | 2003-05-13 | Ckm Diagnostics, Inc. | Electrode array and skin attachment system for noninvasive nerve location and imaging device |
US6609018B2 (en) | 2000-07-27 | 2003-08-19 | Ckm Diagnostics, Inc. | Electrode array and sensor attachment system for noninvasive nerve location and imaging device |
US20080139957A1 (en) * | 2003-03-19 | 2008-06-12 | Church Of Spiritual Technology, Inc. | System For Measuring And Indicating Changes In The Resistance Of A Living Body |
US20150293045A1 (en) * | 2014-04-11 | 2015-10-15 | Texas Instruments Incorporated | Measuring electrode impedance in an impedance measurement circuit |
US10111624B2 (en) * | 2014-04-11 | 2018-10-30 | Texas Instruments Incorporated | Measuring electrode impedance in an impedance measurement circuit |
US10006950B2 (en) | 2014-04-24 | 2018-06-26 | Texas Instruments Incorporated | Impedance measurement circuit |
US10739433B2 (en) | 2016-03-21 | 2020-08-11 | Texas Instruments Incorporated | Calibrating body impedance measurement systems |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: HUBBARD, LAFAYETTE R., SAINT HILL MANOR, EAST GRIN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:CONNERS, RON;MC CORMICK, JOHN;REEL/FRAME:003925/0270;SIGNING DATES FROM 19810911 TO 19810914 |
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Free format text: PATENTED CASE |
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Year of fee payment: 4 |
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Owner name: STARKEY, NORMAN F., TRUSTEE OF THE AUTHOR'S FAMILY Free format text: JUDGMENT OF FINAL DISTRIBUTION FILED JAN. 3, 1989.;ASSIGNOR:STARKEY, NORMAN F., EXECUTOR OF THE ESTATE OF RAN HUBBARD A/K/A LAFAYETTE RONALD HUBBARD, DEC'D.;REEL/FRAME:005021/0278 Effective date: 19880103 |
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