1. A device for indicating changes in the resistance of a living body comprising:
- a resistance measuring circuit having external leads, and adapted to measure resistances within a first range of relatively low variable resistances, to measure resistances within a second range of relatively high variable resistances across a living body and to produce a measured signal;
- an amplifier circuit connected to the resistance measuring circuit and adapted to amplify the measured signal to a perceptible level;
- an indicator circuit connected to said amplifier circuit and adapted to produce the measured signal in a perceptible form; and
- a sensitivity adjustment circuit means connected to said amplifier circuit, connected to said indicator circuit and for automatically increasing sensitivity of said indicator circuit for a high variable resistance in said second range measured in said resistance measuring circuit.
2. The device for indicating changes in the resistance of a living body of claim 1:
- wherein said sensitivity adjustment circuit means is also for automatically adjusting sensitivity of said indicator circuit for a low variable resistance in said first range measured in said resistance measuring circuit.
3. The device for indicating changes in the resistance of a living body of claim 1 wherein:
- said sensitivity adjustment circuit means includes a control circuit.
4. A device for indicating changes in the resistance of a living body comprising:
- a resistance measuring circuit having external leads;
- an amplifier, circuit connected to the resistance measuring circuit;
- an indicator circuit connected to said amplifier circuit;
- a sensitivity adjustment circuit connected to said amplifier circuit, said indicator circuit capable of automatically increasing sensitivity of said indicator circuit for a high variable resistance setting in said resistance measuring circuit; and
- said sensitivity adjustment circuit includes a dual ganged potentiometer.
5. The device for indicating changes in the resistance of a living body of claim 1 wherein:
- said sensitivity adjustment circuit means includes a voltage controlled operational amplifier.
6. A device for indicating changes in the resistance of a living body comprising:
- a resistance measuring circuit having external leads and a manual adjustment potentiometer;
- an amplifier circuit connected to the resistance measuring circuit;
- an indicator circuit connected to said amplifier circuit;
- said amplifier circuit including a calibration circuit operative to automatically adjust the gain of said amplifier circuit in response to movement of said adjustment potentiometer.
7. The device for indicating changes in the resistance of a living body of claim 6 wherein said calibration circuit includes:
- a measured input feedback circuit responsively connected to said resistance measuring circuit;
- a compensation valve control circuit responsively connected to said feedback circuit; and
- a constant amplitude response compensator circuit connected to and responsive to said control circuit.
8. The device for measuring and indicating changes in the resistance of living body of claim 6 wherein said calibration circuit includes a feedback circuit adapted to receive signals representative of the overall resistance of a living body.
9. The device for measuring and indicating changes in the resistance of living a body of claim 8 further including control circuit connected to said feedback circuit and adopted to determine from said input signal a compensation signal corresponding to a change in the gain of the amplifier circuit.
10. The device for measuring and indicating changes in the resistance of a living body of claim 9 further including a compensator circuit adapted to receive said compensation signal and to adjust said amplifier circuit to maintain a generally constant amplitude response.
11. A device for indicating changes in the resistance of a living body comprising:
- a resistance measuring circuit having leads extending therefrom;
- an amplifier circuit having leads extending therefrom;
- an indicator circuit having leads extending therefrom;
- a plurality of manually controlled devices having leads extending therefrom;
- at least one lead extending from each of said circuits and from each of said manually controlled devices; and
- at least one inductor included within said resistance measuring circuit; and within said amplifier circuit
- whereby radio interference conducted through said circuits is reduced.
12. A device for indicating changes in the resistance of a living body comprising:
- a resistance measuring circuit;
- an amplifier circuit;
- an indicator circuit;
- a housing surrounding said resistance measuring circuit, said amplifier circuit and said indicator circuit; and
- a radio frequency insulating paint coating said housing.
13. A method for maintaining a generally constant amplitude response to a predetermined measured input in a device for measuring changes in the resistance of a living body, the device having a resistance measuring circuit, an amplifier circuit and an indicator circuit, comprising:
- initializing said resistance measuring circuit and said amplifier circuit;
- connecting a living body to said resistance measuring circuit;
- establishing the overall resistance in the living body; and
- adjusting the gain of said amplifier circuit according to a predetermined ratio such that a generally constant amplitude response is generated for a measured change in resistance.
14. The device of claim 6 further including a computer interface adapted to provide a simulated measured signal.
15. The device of claim 6 wherein said amplifier circuit includes an op-amp having a capacitor connected in circuit between positive and negative inputs to said op-amp.
16. The device of claim 7 wherein said control circuit further includes:
- a microcontroller connected to said feedback circuit; and
- an analog to digital converter connected to said feedback circuit.
17. The device of claim 7 wherein said control circuit further includes:
- an activation circuit adapted to activate said control circuit upon transition of said manual adjustment potentiometer.
18. The device of claim 7 further including;
- a microcontroller in said control circuit and which is connected to said feedback circuit; and
- computer-implemented software operatively controlling said microcontroller.
19. The device of claim 18 further including a calibration input signal compensator circuit and a digital potentiometer connected to said amplifier circuit.
20. The device of claim 6 further including:
- a microcontroller in said calibration circuit;
- computer-implemented software adapted to configure said calibration circuit, to continuously detect changes in the manual adjustment potentiometer, and to determine and set a resolution mode from a set of predetermined resolution modes.
21. The method of claim 13 further including:
- manually adjusting a potentiometer as part of establishing the overall resistance; and
- setting a resolution mode for establishing overall resistance of the living body to one of a plurality of predetermined resolution modes.
22. The method of claim 21 further adjusting the gain of said amplifier circuit by matching predetermined compensation factor signals to predetermined resistance change values corresponding to changes in the overall resistance in the living body.
