US Patent Class 324
ELECTRICITY: MEASURING AND TESTING



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Current as of: June, 1999
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  DF  CLASS NOTES
300  DF  PARTICLE PRECESSION RESONANCE
301  DF  .~ Using a magnetometer
302  DF  .~.~ To determine direction
303  DF  .~ Using well logging device
304  DF  .~ Using optical pumping or sensing device
305  DF  .~.~ Having particular optical cell structure
306  DF  .~ Determine fluid flow rate
307  DF  .~ Using a nuclear resonance spectrometer system
308  DF  .~.~ Including a test sample and control sample
309  DF  .~.~ To obtain localized resonance within a sample
310  DF  .~.~ By scanning sample frequency spectrum
311  DF  .~.~ With signal decoupling
312  DF  .~.~ By spectrum storage and analysis
313  DF  .~.~ Including polarizing magnetic field/radio frequency tuning
314  DF  .~.~ With conditioning of transmitter signal
315  DF  .~.~ With sample resonant frequency and temperature interdependence
316  DF  .~ Using an electron resonance spectrometer system
317  DF  .~.~ Including a test sample and control sample
318  DF  .~ Spectrometer components
319  DF  .~.~ Polarizing field magnet
320  DF  .~.~.~ With homogeneity control
321  DF  .~.~ Sample holder structure
322  DF  .~.~ Electronic circuit elements
323  DF  OF GEOPHYSICAL SURFACE OR SUBSURFACE IN SITU
324  DF  .~ Including borehole fluid investigation
325  DF  .~.~ To determine fluid entry
326  DF  .~ For small object detection or location
327  DF  .~.~ Using oscillator coupled search head
328  DF  .~.~.~ Of the beat frequency type
329  DF  .~.~ Using movable transmitter and receiver
330  DF  .~ By aerial survey
331  DF  .~.~ For magnetic field detection
332  DF  .~ With radiant energy or nonconductive-type transmitter
333  DF  .~.~ Within a borehole
334  DF  .~.~ With separate pickup
335  DF  .~.~.~ Employing multiple frequencies
336  DF  .~.~.~ To detect transient signals
337  DF  .~.~.~ To detect return wave signals
338  DF  .~.~.~ Within a borehole
339  DF  .~.~.~.~ By induction logging
340  DF  .~.~.~.~.~ To measure susceptibility
341  DF  .~.~.~.~.~ To measure dielectric constant
342  DF  .~.~.~.~.~ Using a toroidal coil
343  DF  .~.~.~.~.~ Using angularly spaced coils
344  DF  .~ With radiant energy or nonconductive-type receiver
345  DF  .~ By magnetic means
346  DF  .~.~ Within a borehole
347  DF  .~ Using electrode arrays, circuits, structure, or supports
348  DF  .~.~ For detecting naturally occurring fields, currents, or potentials
349  DF  .~.~.~ Of the telluric type
350  DF  .~.~.~.~ Including magneto-telluric type
351  DF  .~.~.~ Within a borehole
352  DF  .~.~.~.~ Combined with artificial source measurement
353  DF  .~.~.~.~ With fluid movement or pressure variation
354  DF  .~.~ Coupled to artificial current source
355  DF  .~.~.~ Within a borehole
356  DF  .~.~.~.~ While drilling
357  DF  .~.~.~ Including separate pickup of generated fields or potentials
358  DF  .~.~.~.~ With three electrodes
359  DF  .~.~.~.~ With nonelectrode pickup means
360  DF  .~.~.~.~ Using a pulse-type current source
361  DF  .~.~.~.~.~ With mechanical current reversing means
362  DF  .~.~.~.~.~ To measure induced polarization
363  DF  .~.~.~.~ By varying the path of current flow
364  DF  .~.~.~.~.~ Using frequency variation
365  DF  .~.~.~.~ Offshore
366  DF  .~.~.~.~ For well logging
367  DF  .~.~.~.~.~ Using a pad member
368  DF  .~.~.~.~.~ Cased borehole
369  DF  .~.~.~.~.~ While drilling
370  DF  .~.~.~.~.~ Using surface current electrodes
371  DF  .~.~.~.~.~ Using plural fields
372  DF  .~.~.~.~.~ Between spaced boreholes
373  DF  .~.~.~.~.~ Using current focussing means
374  DF  .~.~.~.~.~.~ Including a pad member
375  DF  .~.~.~.~.~.~ Including plural current focussing arrays
376  DF  OF SUBSURFACE CORE SAMPLE
377  DF  .~ For magnetic properties
378  DF  INTERNAL-COMBUSTION ENGINE IGNITION SYSTEM OR DEVICE
379  DF  .~ With analysis of displayed waveform
380  DF  .~ Electronic ignition system
381  DF  .~.~ With magnetically controlled circuit
382  DF  .~.~ With capacitor discharge circuit
383  DF  .~ By simulating or substituting for a component under test
384  DF  .~ Using plural tests in a conventional ignition system
385  DF  .~ Distributor
386  DF  .~.~ Dwell (i.e., cam angle)
387  DF  .~.~ Condenser
388  DF  .~ Coil
389  DF  .~ Magneto
390  DF  .~ Low or high tension lead
391  DF  .~ Ignition timing
392  DF  .~.~ Using a pulse signal technique
393  DF  .~ In situ testing of spark plug
394  DF  .~.~ With cathode-ray tube display
395  DF  .~.~ Using an illuminating device to indicate spark plug condition
396  DF  .~.~ With an air gap in series with spark plug to indicate spark plug condition
397  DF  .~.~ By shorting the plug to ground to indicate spark plug condition
398  DF  .~.~.~ With air gap in ground circuit
399  DF  .~.~ Wherein a measured electric quantity indicates spark plug condition
400  DF  .~ Spark plug removed or tested in a test fixture
401  DF  .~.~ Using a pressure chamber
402  DF  .~ Apparatus for coupling a measuring instrument to an ignition system
403  DF  ELECTRIC LAMP OR DISCHARGE DEVICE
404  DF  .~ Cathode-ray tube
405  DF  .~ Vacuum tube
406  DF  .~.~ Plural tubes in the testing circuit
407  DF  .~.~ Testing circuit for diverse-type tube
408  DF  .~.~ Circuit for making diverse test
409  DF  .~.~ Testing discharge space characteristic (e.g., emission)
410  DF  .~.~.~ With application of current or potential to the discharge control means
411  DF  .~.~.~.~ Pulsating or alternating current or potential for the discharge control means
412  DF  .~.~.~.~.~ Pulsating or alternating current for the anode
413  DF  .~.~ Shock testing
414  DF  .~ Electric lamp
415  DF  ELECTROMECHANICAL SWITCHING DEVICE
416  DF  .~ Voltage regulator
417  DF  .~ Thermostat switch
418  DF  .~ Relay
419  DF  .~.~ Reed switch
420  DF  .~.~ To evaluate contact chatter
421  DF  .~.~ To evaluate contact resistance
422  DF  .~.~ To evaluate contact sequence of operation
423  DF  .~.~ To evaluate contact response time
424  DF  .~ Circuit breaker
425  DF  ELECTROLYTE PROPERTIES
426  DF  .~ Using a battery testing device
427  DF  .~.~ To determine ampere-hour charge capacity
428  DF  .~.~.~ Including an integrating device
429  DF  .~.~ To determine load/no-load voltage
430  DF  .~.~ To determine internal battery impedance
431  DF  .~.~ With temperature compensation of measured condition
432  DF  .~.~ To determine battery electrolyte condition
433  DF  .~.~ To compare battery voltage with a reference voltage
434  DF  .~.~ To determine plural cell condition
435  DF  .~.~ Having particular meter scale or indicator
436  DF  .~.~ Including oscillator in measurement circuit
437  DF  .~.~ Including probe structure
438  DF  .~ Using a pH determining device
439  DF  .~ Using a conductivity determining device
440  DF  .~.~ Which includes a dropping mercury cell
441  DF  .~.~ Which includes a temperature responsive element
442  DF  .~.~ Which includes an oscillator
443  DF  .~.~ Having a bridge circuit
444  DF  .~.~ Which includes current and voltage electrodes
445  DF  .~.~ Having inductance probe structure
446  DF  .~.~ Having conductance probe structure
447  DF  .~.~.~ With movable or adjustable electrode
448  DF  .~.~.~ With concentric electrodes
449  DF  .~.~.~ With axially arranged electrodes
450  DF  .~.~ Which includes particular cell container structure
451  DF  A MATERIAL PROPERTY USING THERMOELECTRIC PHENOMENON
452  DF  A MATERIAL PROPERTY USING ELECTROSTATIC PHENOMENON
453  DF  .~ In a liquid
454  DF  .~ Frictionally induced
455  DF  .~ Corona induced
456  DF  .~ For flaw detection
457  DF  ELECTROSTATIC FIELD
458  DF  .~ Using modulation-type electrometer
459  DF  USING IONIZATION EFFECTS
460  DF  .~ For monitoring pressure
461  DF  .~.~ Using a radioactive substance
462  DF  .~.~ Using thermionic emissions
463  DF  .~.~ Using a magnetic field
464  DF  .~ For analysis of gas, vapor, or particles of matter
465  DF  .~.~ Using electronegative gas sensor
466  DF  .~.~ Using a filter
467  DF  .~.~ Using test material desorption
468  DF  .~.~ Using thermal ionization
469  DF  .~.~ Using a radioactive substance
470  DF  .~.~ Using thermionic emission
200  DF  MAGNETIC
201  DF  .~ Susceptibility
202  DF  .~ Calibration
203  DF  .~ Curie point determination
204  DF  .~ Fluid material examination
205  DF  .~ Permanent magnet testing
206  DF  .~ Movable random length material measurement
207.11  DF  .~ Displacement
207.12  DF  .~.~ Compensation for measurement
207.13  DF  .~.~ Having particular sensor means
207.14  DF  .~.~.~ Diverse sensors
207.15  DF  .~.~.~ Inductive
207.16  DF  .~.~.~.~ Electrically energized
207.17  DF  .~.~.~.~.~ Separate pick-up
207.18  DF  .~.~.~.~.~ Differential type (e.g., LVDT)
207.19  DF  .~.~.~.~.~ Differential bridge circuit
207.2  DD  .~.~.~ Hall effect
207.21  DF  .~.~.~ Magnetoresistive
207.22  DF  .~.~ Having particular sensed object
207.23  DF  .~.~ Plural measurements (e.g., linear and rotary)
207.24  DF  .~.~ Linear
207.25  DF  .~.~ Rotary
207.26  DF  .~.~ Approach or retreat
209  DF  .~ Stress in material measurement
210  DF  .~ Magnetic information storage element testing
211  DF  .~.~ Memory core storage element testing
212  DF  .~.~ Dynamic information element testing
213  DF  .~ Magnetic recording medium on magnetized object records object field
214  DF  .~ By paramagnetic particles
215  DF  .~.~ With pattern enhancing additive
216  DF  .~.~ Flaw testing
217  DF  .~ Railroad rail flaw testing
218  DF  .~.~ Rail joint cutout
219  DF  .~ Magnetic sensor within material
220  DF  .~.~ Sensor supported, positioned, or moved within pipe
221  DF  .~.~.~ Borehole pipe testing
222  DF  .~ Hysteresis or eddy current loss testing
223  DF  .~ Hysteresis loop curve display or recording
224  DF  .~ With temperature control of material or element of test circuit
225  DF  .~ With compensation for test variable
226  DF  .~ Combined
227  DF  .~ Plural tests
228  DF  .~ With means to create magnetic field to test material
229  DF  .~.~ Thickness measuring
230  DF  .~.~.~ Layer or layered material
231  DF  .~.~.~ With backing member
232  DF  .~.~ Plural magnetic fields in material
233  DF  .~.~ With phase sensitive element
234  DF  .~.~ Electrically energized nonforce type sensor
235  DF  .~.~.~ Noncoil type
236  DF  .~.~.~ Oscillator type
237  DF  .~.~.~.~ Material flaw testing
238  DF  .~.~.~ Material flaw testing
239  DF  .~.~ Induced voltage-type sensor
240  DF  .~.~.~ Material flaw testing
241  DF  .~.~.~.~ Opposed induced voltage sensors
242  DF  .~.~.~.~ Plural sensors
243  DF  .~.~.~ Plural sensors
244  DF  .~ Magnetometers
244.1  DF  .~.~ Optical
245  DF  .~.~ Plural sensor axis misalignment correction
246  DF  .~.~ With means to align field sensor with magnetic field sensed
247  DF  .~.~ Nonparallel plural magnetic sensors
248  DF  .~.~ Superconductive magnetometers
249  DF  .~.~ Thin film magnetometers
250  DF  .~.~ Electronic tube or microwave magnetometers
251  DF  .~.~ Hall plate magnetometers
252  DF  .~.~ Semiconductor type solid-state or magnetoresistive magnetometers
253  DF  .~.~ Saturable core magnetometers
254  DF  .~.~.~ Second harmonic type
255  DF  .~.~.~ Peak voltage type
256  DF  .~.~ Energized movable sensing coil magnetometers
257  DF  .~.~ Moving coil magnetometer
258  DF  .~.~ Fixed coil magnetometer
259  DF  .~.~ Movable magnet or magnetic member interacts with magnetic field
260  DF  .~ Magnetic field detection devices
261  DF  .~.~ With support for article
262  DF  .~ Magnetic test structure elements
263  DF  .~ Current through test material forms test magnetic field
500  DF  FAULT DETECTING IN ELECTRIC CIRCUITS AND OF ELECTRIC COMPONENTS
501  DF  .~ Using radiant energy
502  DF  .~ In an ignitor or detonator
503  DF  .~ In vehicle wiring
504  DF  .~.~ With trailer
505  DF  .~.~ Combined with window glass
506  DF  .~ Combined with a flashlight
507  DF  .~.~ With fuse testing attachment
508  DF  .~ With electric power receptacle for line wire testing
509  DF  .~ Of ground fault indication
510  DF  .~.~ Of electrically operated apparatus (power tool, appliance, machine, etc.)
511  DF  .~ Of electrically operated apparatus (power tool, appliance, machine, etc.)
512  DF  .~ For fault location
513  DF  .~.~ Where component moves while under test
514  DF  .~.~.~ By exposing component to liquid or gas while under test
515  DF  .~.~.~ Using a particular sensing electrode
516  DF  .~.~.~.~ Metal chain
517  DF  .~.~.~.~ Wire bristles
518  DF  .~.~.~.~ Metal pellets or beads
519  DF  .~.~ By capacitance measuring
520  DF  .~.~ By frequency sensitive or responsive detection
521  DF  .~.~ By phase sensitive or responsive detection
522  DF  .~.~ By voltage or current measuring
523  DF  .~.~.~ Of an applied test signal
524  DF  .~.~.~ Polarity responsive
525  DF  .~.~ By resistance or impedance measuring
526  DF  .~.~.~ Using a bridge circuit
527  DF  .~.~ By applying a test signal
528  DF  .~.~.~ Tracing test signal to fault location
529  DF  .~.~.~.~ Using a magnetic field sensor
530  DF  .~.~.~.~ Using an electric field sensor
531  DF  .~.~.~ At fault site
532  DF  .~.~.~ Using time measuring
533  DF  .~.~.~.~ Of reflected test signal
534  DF  .~.~ By reflection technique
535  DF  .~.~ By time measuring
536  DF  .~.~ By spark or arc discharge
537  DF  .~ Of individual circuit component or element
750  DF  .~.~ System sensing fields adjacent device under test (DUT)
751  DF  .~.~.~ Using electron beam probe
752  DF  .~.~.~ Using light probe
753  DF  .~.~.~ Using electro-optic device
754  DF  .~.~ With probe elements
755  DF  .~.~.~ Internal of or on support for device under test (DUT)
756  DF  .~.~.~ Contact confirmation
757  DF  .~.~.~ Probe contact enhancement
758  DF  .~.~.~ Probe alignment or positioning
759  DF  .~.~.~ With recording of test results on DUT
760  DF  .~.~.~ With temperature control
761  DF  .~.~.~ Pin
762  DF  .~.~.~ Cantilever
763  DF  .~.~ DUT including test circuit
764  DF  .~.~ With identification of DUT
765  DF  .~.~ Test of semiconductor device
766  DF  .~.~.~ With barrier layer
767  DF  .~.~.~.~ Diode
768  DF  .~.~.~.~ Bipolar transistor
769  DF  .~.~.~.~ Field effect transistor
770  DF  .~.~ Liquid crystal device test
771  DF  .~.~ Power supply test
772  DF  .~.~ Motor or generator fault tests
538  DF  .~.~ Electrical connectors
539  DF  .~.~ Multiconductor cable
540  DF  .~.~.~ With sequencer
541  DF  .~.~.~ For insulation fault
542  DF  .~.~.~ Having a light or sound indicator
543  DF  .~.~ Single conductor cable
544  DF  .~.~.~ For insulation fault
545  DF  .~.~ Armature or rotor
546  DF  .~.~ Winding or coil
547  DF  .~.~.~ Transformer
548  DF  .~.~ Capacitor
549  DF  .~.~ Resistor
550  DF  .~.~ Fuse
551  DF  .~.~ Insulation
552  DF  .~.~.~ Bushing
553  DF  .~.~.~ Oil
554  DF  .~.~.~ Sheet material
555  DF  .~ Instruments and devices for fault testing
556  DF  .~.~ Having a lamp or light indicator
557  DF  FOR INSULATION FAULT OF NONCIRCUIT ELEMENTS
558  DF  .~ Where element moves while under test
559  DF  .~ Where a moving sensing electrode scans a stationary element under test
600  DF  IMPEDANCE, ADMITTANCE OR OTHER QUANTITIES REPRESENTATIVE OF ELECTRICAL STIMULUS/RESPONSE RELATIONSHIPS
601  DF  .~ Calibration
602  DF  .~ With auxiliary means to condition stimulus/response signals
603  DF  .~.~ For excitation
604  DF  .~.~.~ Including marker signal generator circuit
605  DF  .~.~ For response signal evaluation or processing
606  DF  .~.~.~ Including a signal comparison circuit
607  DF  .~.~.~ Including a conversion (e.g., A->D or D-> A) process
608  DF  .~.~.~ Including a ratiometric function
609  DF  .~.~ For sensing
610  DF  .~.~.~ Including a bridge circuit
611  DF  .~.~.~ Including a remote type circuit
612  DF  .~ Parameter related to the reproduction or fidelity of a signal affected by a circuit under test
613  DF  .~.~ Noise
614  DF  .~.~.~ Signal to noise ratio or noise figure
615  DF  .~.~ Transfer function type characteristics
616  DF  .~.~.~ Gain or attenuation
617  DF  .~.~.~ Response time or phase delay
618  DF  .~.~.~ Transient response or transient recovery time (e.g., damping)
619  DF  .~.~.~ Selective type characteristics
620  DF  .~.~ Distortion
621  DF  .~.~.~ Envelope delay
622  DF  .~.~.~ Phase
623  DF  .~.~.~ Harmonic
624  DF  .~.~.~ Intermodulation
625  DF  .~.~.~ Dissymmetry or asymmetry
626  DF  .~.~.~ Nonlinearity
627  DF  .~.~ Shielding effectiveness (SE)
628  DF  .~.~.~ Circuit interference (e.g., crosstalk) measurement
629  DF  .~ Distributive type parameters
630  DF  .~.~ Plural diverse parameters
631  DF  .~.~ Using wave polarization (e.g., field rotation)
632  DF  .~.~ Using particular field coupling type (e.g., fringing field)
633  DF  .~.~ Using resonant frequency
634  DF  .~.~.~ To determine water content
635  DF  .~.~.~ To determine dimension (e.g., distance or thickness)
636  DF  .~.~.~ With a resonant cavity
637  DF  .~.~ Using transmitted or reflected microwaves
638  DF  .~.~.~ Scattering type parameters (e.g., complex reflection coefficient)
639  DF  .~.~.~ Where energy is transmitted through a test substance
640  DF  .~.~.~.~ To determine water content
641  DF  .~.~.~.~ To determine insertion loss
642  DF  .~.~.~ Where energy is reflected (e.g., reflectometry)
643  DF  .~.~.~.~ To determine water content
644  DF  .~.~.~.~ To determine dimension (e.g., distance or thickness)
645  DF  .~.~.~.~ Having standing wave pattern
646  DF  .~.~.~.~ To determine reflection coefficient
647  DF  .~.~ Using a comparison or difference circuit
648  DF  .~.~.~ With a bridge circuit
649  DF  .~ Lumped type parameters
650  DF  .~.~ Using phasor or vector analysis
651  DF  .~.~.~ With a bridge circuit
652  DF  .~.~ Of a resonant circuit
653  DF  .~.~ For figure of merit or Q value
654  DF  .~.~ Using inductive type measurement
655  DF  .~.~.~ Including a tuned or resonant circuit
656  DF  .~.~.~ Including a comparison or difference circuit
657  DF  .~.~.~.~ Using a bridge circuit
658  DF  .~.~ Using capacitive type measurement
659  DF  .~.~.~ With loss characteristic evaluation
660  DF  .~.~.~ With variable electrode area
661  DF  .~.~.~ With variable distance between capacitor electrodes
662  DF  .~.~.~.~ To determine dimension (e.g., thickness or distance)
663  DF  .~.~.~ Where a material or object forms part of the dielectric being measured
664  DF  .~.~.~.~ To determine water content
665  DF  .~.~.~.~.~ By comparison or difference circuit
666  DF  .~.~.~.~.~.~ Including a bridge circuit
667  DF  .~.~.~.~.~ By frequency signal response, change or processing circuit
668  DF  .~.~.~.~.~.~ Including a tuned or resonant circuit
669  DF  .~.~.~.~.~ With compensation means
670  DF  .~.~.~.~.~.~ For temperature variations
671  DF  .~.~.~.~ To determine dimension (e.g., dielectric thickness)
672  DF  .~.~.~.~ By comparison or difference circuit
673  DF  .~.~.~.~.~ Including a bridge circuit
674  DF  .~.~.~.~ By frequency signal response, change or processing circuit
675  DF  .~.~.~.~.~ Including a tuned or resonant circuit
676  DF  .~.~.~ With pulse signal processing circuit
677  DF  .~.~.~.~ Including R/C time constant circuit
678  DF  .~.~.~.~ Including charge or discharge cycle circuit
679  DF  .~.~.~ With comparison or difference circuit
680  DF  .~.~.~.~ Including a bridge circuit
681  DF  .~.~.~ With frequency signal response, change or processing circuit
682  DF  .~.~.~.~ Including a tuned or resonant circuit
683  DF  .~.~.~ With phase signal processing circuit
684  DF  .~.~.~ With compensation means
685  DF  .~.~.~.~ For temperature variation
686  DF  .~.~.~ With a capacitive sensing means
687  DF  .~.~.~.~ Having fringing field coupling
688  DF  .~.~.~.~ Including a guard or ground electrode
689  DF  .~.~.~.~ To determine water content
690  DF  .~.~.~.~ Including a probe type structure
691  DF  .~.~ Using resistance or conductance measurement
692  DF  .~.~.~ With living organism condition determination using conductivity effects
693  DF  .~.~.~ With object or substance characteristic determination using conductivity effects
694  DF  .~.~.~.~ To determine water content
695  DF  .~.~.~.~.~ Where the object moves while under test
696  DF  .~.~.~.~.~ With a probe structure
697  DF  .~.~.~.~ For interface
698  DF  .~.~.~.~ To determine oil qualities
699  DF  .~.~.~.~ To determine dimension (e.g., distance or thickness)
700  DF  .~.~.~.~.~ Including corrosion or erosion
701  DF  .~.~.~.~ Where the object moves while under test
702  DF  .~.~.~ With radiant energy effects
703  DF  .~.~.~.~ Including heating
704  DF  .~.~.~ With ratio determination
705  DF  .~.~.~ With comparison or difference circuit
706  DF  .~.~.~.~ Including a bridge circuit
707  DF  .~.~.~ With frequency response, change or processing circuit
708  DF  .~.~.~.~ Including a tuned or resonant circuit
709  DF  .~.~.~ With phase signal processing circuit
710  DF  .~.~.~ With pulse signal processing circuit
711  DF  .~.~.~.~ Including R/C time constant circuit
712  DF  .~.~.~.~ Including a digital or logic circuit
713  DF  .~.~.~ With voltage or current signal evaluation
714  DF  .~.~.~.~ Including a potentiometer
715  DF  .~.~.~.~ Including a particular probing technique (e.g., four point probe)
716  DF  .~.~.~.~.~ To determine dimension (e.g., distance or thickness)
717  DF  .~.~.~.~.~ To determine material composition
718  DF  .~.~.~.~.~ To detect a flaw or defect
719  DF  .~.~.~ With semiconductor or IC materials quality determination using conductivity effects
720  DF  .~.~.~ With compensation means
721  DF  .~.~.~.~ For temperature variation
722  DF  .~.~.~ Device or apparatus determines conductivity effects
723  DF  .~.~.~.~ Potentiometer
724  DF  .~.~.~.~ Using a probe type structure
725  DF  .~ Using a particular bridge circuit
726  DF  .~ Transformer testing (e.g., ratio)
727  DF  .~ Piezoelectric crystal testing (e.g., frequency, resistance)
66  DF  CONDUCTOR IDENTIFICATION OR LOCATION (E.G., PHASE IDENTIFICATION)
67  DF  .~ Inaccessible (at test point) conductor (e.g., buried in wall)
160  DF  ELECTRICAL SPEED MEASURING
161  DF  .~ Speed comparing means
162  DF  .~ With acceleration measuring means
163  DF  .~ Including speed analog electrical signal generator
164  DF  .~.~ Eddy current generator type (e.g., tachometer)
165  DF  .~.~ With direction indicator
166  DF  .~ Including speed-related frequency generator
167  DF  .~.~ Including rotating magnetic field actuated indicator
168  DF  .~.~ Including periodic switch
169  DF  .~.~.~ In ignition system
170  DF  .~.~.~.~ High voltage speed signal type
171  DF  .~.~.~ With extent-of-travel indicator
172  DF  .~.~ Including synchronized recording medium
173  DF  .~.~ Including magnetic detector
174  DF  .~.~.~ Permanent magnet type
175  DF  .~.~ Including radiant energy detector
176  DF  .~ Including object displacement varied variable circuit impedance
177  DF  .~ Including motor current or voltage sensor
178  DF  .~ Including "event" sensing means
179  DF  .~.~ Magnetic field sensor
180  DF  .~.~ Mechanically actuated switch
71.1  DF  DETERMINING NONELECTRIC PROPERTIES BY MEASURING ELECTRIC PROPERTIES
71.2  DF  .~ Erosion
71.3  DF  .~ Beam of atomic particles
71.4  DF  .~ Particle counting
71.5  DF  .~ Semiconductors for nonelectrical property
71.6  DF  .~ Superconductors
72  DF  TESTING POTENTIAL IN SPECIFIC ENVIRONMENT (E.G., LIGHTNING STROKE)
72.5  DF  .~ Voltage probe
73.1  DF  PLURAL, AUTOMATICALLY SEQUENTIAL TESTS
74  DF  TESTING AND CALIBRATING ELECTRIC METERS (E.G., WATT-HOUR METERS)
75  DF  .~ By stroboscopic means
76.11  DF  MEASURING, TESTING, OR SENSING ELECTRICITY, PER SE
76.12  DF  .~ Analysis of complex waves
76.13  DF  .~.~ Amplitude distribution
76.14  DF  .~.~.~ Radiometer (e.g., microwave, etc.)
76.15  DF  .~.~.~ With sampler
76.16  DF  .~.~.~ With counter
76.17  DF  .~.~.~ With integrator
76.18  DF  .~.~.~ With slope detector
76.19  DF  .~.~ Frequency spectrum analyzer
76.21  DF  .~.~.~ By Fourier analysis
76.22  DF  .~.~.~ Real-time spectrum analyzer
76.23  DF  .~.~.~ With mixer
76.24  DF  .~.~.~ With sampler
76.25  DF  .~.~.~ With slope detector
76.26  DF  .~.~.~ Scanning-panoramic receiver
76.27  DF  .~.~.~.~ With particular sweep circuit
77.11  DF  .~.~.~ Nonscanning
76.28  DF  .~.~.~.~ Digital filter
76.29  DF  .~.~.~.~ With filtering
76.31  DF  .~.~.~.~.~ Parallel filters
76.32  DF  .~.~.~.~.~.~ With space discharge device
76.33  DF  .~.~.~.~ Correlation
76.34  DF  .~.~.~.~.~ With space discharge device
76.35  DF  .~.~.~.~ With delay line
76.36  DF  .~.~.~.~ With optics
76.37  DF  .~.~.~.~.~ Bragg cell
76.38  DF  .~.~ With sampler
76.39  DF  .~ Frequency of cyclic current or voltage (e.g., cyclic counting etc.)
76.41  DF  .~.~ Frequency comparison, (e.g., heterodyne, etc.)
76.42  DF  .~.~.~ With sampler
76.43  DF  .~.~.~ With plural mixers
76.44  DF  .~.~.~ With filtering
76.45  DF  .~.~.~.~ Bandpass
76.46  DF  .~.~.~.~ Plural
76.47  DF  .~.~.~ Digital output
76.48  DF  .~.~.~.~ With counter
76.49  DF  .~.~ Tuned mechanical resonator (e.g., reed, piezocrystal, etc.)
76.51  DF  .~.~ By tuning (e.g., to resonance,etc.)
76.52  DF  .~.~ By phase comparison
76.53  DF  .~.~.~ With phase lock
76.54  DF  .~.~.~ With delay line
76.55  DF  .~.~.~ Digital output
76.56  DF  .~.~.~.~ With microwave frequency detection
76.57  DF  .~.~.~.~ With tone detection
76.58  DF  .~.~.~.~ With sampler
76.59  DF  .~.~.~.~ With multiplexing
76.61  DF  .~.~.~.~ With memory
76.62  DF  .~.~.~.~ With counter
76.63  DF  .~.~.~.~.~ Using register
76.64  DF  .~.~.~.~.~ Plural
76.65  DF  .~.~.~.~ With space discharge device
76.66  DF  .~.~.~ With capacitive energy storage
76.67  DF  .~.~.~.~ With space discharge device
76.68  DF  .~.~.~ With filtering
76.69  DF  .~.~.~ Current output proportional to frequency
76.71  DF  .~.~.~ Nulling circuit
76.72  DF  .~.~.~ Qualitative output
76.73  DF  .~.~.~ With saturable device
76.74  DF  .~.~.~ Deviation measurement
76.75  DF  .~.~ Having inductive sensing
76.76  DF  .~.~ With space discharge device
76.77  DF  .~ Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, etc.)
76.78  DF  .~.~ Quadrature sensing
76.79  DF  .~.~ Feedback control, electrical
76.81  DF  .~.~ Feedback control, mechanical
76.82  DF  .~.~ Digital output
76.83  DF  .~.~ Analog output
84  DF  .~.~ With waveguide (e.g., coaxial cable)
85  DF  .~.~ With frequency conversion
86  DF  .~.~ Polyphase (e.g., phase angle, phase rotation or sequence)
87  DF  .~.~ With nonlinear device (e.g., saturable reactor, rectifier), discharge device (e.g., gas tube) or lamp
88  DF  .~.~.~ Cathode ray
89  DF  .~.~.~ Space discharge control means (e.g., grid)
90  DF  .~.~ Electrodynamometer instrument
91  DF  .~.~ Synchroscope type
92  DF  .~ Fluid (e.g., thermal expansion)
93  DF  .~.~ Conductive field (e.g., mercury)
94  DF  .~.~.~ Electrolytic
95  DF  .~ With waveguide or long line
96  DF  .~ Using radiant energy
97  DF  .~.~ Light beam type (e.g., mirror galvanometer, parallax-free scale)
98  DF  .~ Balancing (e.g., known/unknown voltage comparison, bridge, rebalancing)
99 R  DF  .~.~ Automatic
100  DF  .~.~.~ With recording
99 D  DF  .~.~.~ Digital voltmeters
101  DF  .~ Non-rebalancing bridge
102  DF  .~ Transient or portion of cyclic
103 R  DF  .~ Demand, excess, maximum or minimum (e.g., separate meters for positive and negative power, peak voltmeter)
104  DF  .~.~ Thermal (e.g., actuation)
103 P  DF  .~.~ Peak voltmeters
105  DF  .~ Thermal (e.g., compensation)
106  DF  .~.~ Actuation
107  DF  .~ Polyphase
108  DF  .~.~ Positive, negative or zero sequence
109  DF  .~ Electrostatic attraction or piezoelectric
110  DF  .~ Meter protection or fraud combatting
111  DF  .~ With storage means for voltage or current (e.g., condenser banks)
112  DF  .~.~ Tape, sheet (e.g., disk) or wire (e.g., magnetic) storage
113  DF  .~ Recording
114  DF  .~ Plural meters (e.g., plural movements in one case)
115  DF  .~ Plural ranges, scales or registration rates
116  DF  .~.~ With register (e.g., discount type, demand penalty)
117 R  DF  .~ Magnetic saturation (e.g., in field or in amplifier)
117 H  DF  .~.~ Hall effect
118  DF  .~ Modulator/demodulator
119  DF  .~ With rectifier (e.g., A.C. to D.C.)
120  DF  .~ With voltage or current conversion (e.g., D.C. to A.C., 60 to 1000)
121 R  DF  .~ Cathode ray (e.g., magic eye)
121 E  DF  .~.~ Magic eye indicators
122  DF  .~ Gaseous discharge (e.g., spark gap voltmeter)
123 R  DF  .~ With amplifier or space discharge device
124  DF  .~.~ Inverted amplifier
123 C  DF  .~.~ Feedback amplifiers
125  DF  .~ Inertia control, instrument damping and vibration damping
126  DF  .~ With coupling means (e.g., attenuator, shunt)
127  DF  .~.~ Transformer (e.g., split core admits conductor carrying unknown current)
128  DF  .~.~ Selective filter
129  DF  .~ Polepiece (e.g., split) admits nonunitary input conductor
130  DF  .~ Self-calibration
131  DF  .~ Suppressed zero
132  DF  .~ Nonlinear (e.g., Thyrite)
133  DF  .~ Nonquantitative (e.g., hot-line indicator, polarity tester)
134  DF  .~ With commutator or reversing or pulsating switch (e.g., D.C. watt-hour meter)
135  DF  .~.~ Oscillating
136  DF  .~ With rolling wheel or ball (e.g., transmission, integrating)
137  DF  .~ Eddy current rotor (e.g., A.C. integrating wattmeter)
138  DF  .~.~ With phase adjustment
139  DF  .~ Motor-driven, time-controlled or oscillating (e.g., ratchet)
140 R  DF  .~ Plural inputs (e.g., summation, ratio)
141  DF  .~.~ Voltamperes (real or reactive)
142  DF  .~.~ Watts
140 D  DF  .~.~ Ratio
143  DF  .~ Plural active motor elements (e.g., for two crossed pointers)
144  DF  .~ With electromagnetic field (e.g., dynamometer)
145  DF  .~.~ Solenoid plunger type
146  DF  .~.~ With permanent magnet (e.g., field, vane)
147  DF  .~.~ Soft iron vane
149  DF  .~ With probe, prod or terminals
150  DF  .~ Eccentrically pivoted coil
151 R  DF  .~ With permanent magnet
152  DF  .~.~ Drag magnet
151 A  DF  .~.~ Permanent magnet core
153  DF  .~ With register
154 R  DF  .~ With rotor (e.g., filar suspension, zero set, balancing)
155  DF  .~.~ With pivot (e.g., internal friction compensation, anticreep)
154 PB  DF  .~.~ Pointer and bearing details
156  DF  .~ Casings
157  DF  .~ Combined
158.1  DF  MISCELLANEOUS
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CROSS-REFERENCE ART COLLECTION
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800  DF  DIVINING RODS