|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

|  | G01 |
MEASURING (counting Fulltext... Hierarchy... Expanded...G06M); TESTING

|  | G01 |
Note(s) This class covers, in addition to "true" measuring instruments, other indicating or recording devices of analogous construction, and also signalling or control devices insofar as they are concerned with measurement (as defined in Note 2 below) and are not specially adapted to the particular purpose of signalling or control. In this class, the following term is used with the meaning indicated: "measuring" is used to cover considerably more than its primary or basic meaning. In this primary sense, it means finding a numerical expression of the value of a variable in relation to a unit or datum or to another variable of the same nature, e.g. expressing a length in terms of another length as in measuring a length with a scale; the value may be obtained directly (as just suggested) or by measuring some other variable of which the value can be related to the value of the required variable, as in measuring a change in temperature by measuring a resultant change in the length of a column of mercury. However, since the same device or instrument may, instead of giving an immediate indication, be used to produce a record or to initiate a signal to produce an indication or control effect, or may be used in combination with other devices or instruments to give a conjoint result from measurement of two or more variables of the same or different kinds, it is necessary to interpret "measuring" as including also any operation that would make it possible to obtain such a numerical expression by the additional use of some way of converting a value into figures. Thus the expression in figures may be actually made by a digital presentation or by reading a scale, or an indication of it may be given without the use of figures, e.g. by some perceptible feature (variable) of the entity (e.g. object, substance, beam of light) of which the variable being measured is a property or condition or by an analogue of such a feature (e.g. the corresponding position of a member without any scale, a corresponding voltage generated in some way). In many cases there is no such value indication but only an indication of difference or equality in relation to a standard or datum (of which the value may or may not be known in figures); the standard or datum may be the value of another variable of the same nature but of a different entity (e.g. a standard measure) or of the same entity at a different time. In its simplest form, measurement may give merely an indication of presence or absence of a certain condition or quality, e.g. movement (in any direction or in a particular direction), or whether a variable exceeds a predetermined value. Attention is drawn to the Notes following the titles of class Fulltext... Hierarchy... Expanded...B81 and subclass Fulltext... Hierarchy... Expanded...B81B relating to "micro-structural devices" and "micro-structural systems" and the Notes following the title of subclass Fulltext... Hierarchy... Expanded...B82B relating to "nano-structures". [7] Attention is drawn to the Notes following the title of section G, especially as regards the definition of the term "variable". In many measuring arrangements, a first variable to be measured is transformed into a second, or further, variables. The second, or further, variables may be (a) a condition related to the first variable and produced in a member, or (b) a displacement of a member. Further transformation may be needed. [6] When classifying such an arrangement, (i) the transformation step, or each transformation step, that is of interest is classified, or (ii) if interest lies only in the system as a whole, the first variable is classified in the appropriate place. [6] This is particularly important where two or more conversions take place, for instance where a first variable, for example pressure, is transformed into a second variable, for example an optical property of a sensing body, and that second variable is expressed by means of a third variable, for example an electric effect. In such a case, the following classification places should be considered: the place for the transformation of the first variable, that for sensing the condition caused by that variable, subclass Fulltext... Hierarchy... Expanded...G01D for expression of the measurement, and finally the place for the overall system, if any. [6] The measurement of change in the value of a physical property is classified in the same subclass as the measurement of that physical property, e.g. measurement of expansion of length is classified in subclass Fulltext... Hierarchy... Expanded...G01B.

|  | G01R |
MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (measuring physical variables of any kind by conversion into electric variables, see Note (4) following the title of class Fulltext... Hierarchy... Expanded...G01; measuring diffusion of ions in an electric field, e.g. electrophoresis, electro-osmosis, Fulltext... Hierarchy... Expanded...G01N; investigating non-electric or non-magnetic properties of materials by using electric or magnetic methods Fulltext... Hierarchy... Expanded...G01N; indicating correct tuning of resonant circuits Fulltext... Hierarchy... Expanded...H03J 3/12; monitoring electronic pulse counters Fulltext... Hierarchy... Expanded...H03K 21/40; monitoring operation of communication systems Fulltext... Hierarchy... Expanded...H04)

|  | G01R |
Note(s) This subclass covers: measuring all kinds of electric or magnetic variables directly or by derivation from other electric or magnetic variables; measuring all kinds of electric or magnetic properties of materials; testing electric or magnetic devices, apparatus or networks (e.g. discharge tubes, amplifiers) or measuring their characteristics; indicating presence or sign of current or voltage; NMR, EPR or other spin-effect apparatus, not specially adapted for a particular application; [5] equipment for generating signals to be used for carrying out such tests and measurements. In this subclass, the following terms or expressions are used with the meanings indicated: "measuring" includes investigating; "instruments" or "measuring instruments" means electro-mechanical measuring mechanisms; "arrangements for measuring" means apparatus, circuits, or methods for measuring; Attention is drawn to the Notes following the title of class Fulltext... Hierarchy... Expanded...G01. In this subclass, instruments or arrangements for measuring electric variables are classified in the following way: [8] Electromechanical instruments where the measured electric variables direcly effect the indication of the measured value, including combined effects of two or more values, are classified in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 5/00-G01R 11/00. [8] Details common to different types of the instruments covered by groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 5/00-G01R 11/00 are classified in group Fulltext... Hierarchy... Expanded...G01R 1/00. [8] Arrangements involving circuitry to obtain an indication of a measured value by deriving, calculating or otherwise processing electric variables, e.g. by comparison with another value, are classified in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 17/00-G01R 29/00. [8] Details common to different types of arrangements covered by groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 17/00-G01R 29/00 are classified in group Fulltext... Hierarchy... Expanded...G01R 15/00. [8] In this subclass, group Fulltext... Hierarchy... Expanded...G01R 17/00 takes precedence over groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 19/00-G01R 31/00.

|  | G01R |
Subclass index
ELECTRIC MEASURING INSTRUMENTS |
In general | 5/00, 7/00, 9/00
Details | 1/00
Manufacture; calibrating, testing | 3/00; 35/00
ELECTROMECHANICAL MEASUREMENT OF TIME INTEGRAL OF POWER OR CURRENT | 11/00
MEASURING ELECTRIC VARIABLES |
Details of measuring arrangements | 11/02, 15/00
Arrangements for displaying | 13/00
Involving comparison with a reference value | 17/00
Current or voltage; power, power factor; time integral of power or current; frequency; resistance, reactance, impedance | 19/00; 21/00; 22/00; 23/00; 27/00
Other variables | 25/00, 29/00
TESTING ELECTRIC PROPERTIES OR LOCATING FAULTS | 31/00
MEASURING MAGNETIC VARIABLES | 33/00

P:80 |  | G01R 1/00 |
Details of instruments or arrangements of the types included in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 5/00-G01R 13/00 and Fulltext... Hierarchy... Expanded...G01R 31/00 (constructional details particular to arrangements for measuring the electric consumption Fulltext... Hierarchy... Expanded...G01R 11/02) [3,8]

|  | G01R 1/02 |
· | General constructional details (details of a kind applicable to measuring arrangements not specially adapted for a specific variable Fulltext... Hierarchy... Expanded...G01D 7/00)

|  | G01R 1/04 |
· · | Housings; Supporting members; Arrangements of terminals

|  | G01R 1/06 |
· · | Measuring leads; Measuring probes (Fulltext... Hierarchy... Expanded...G01R 19/145, Fulltext... Hierarchy... Expanded...G01R 19/165 take precedence; end pieces for leads Fulltext... Hierarchy... Expanded...H01R 11/00) [3]

|  | G01R 1/067 |
· · · | Measuring probes [3]

|  | G01R 1/07 |
· · · · | Non contact-making probes [6]

|  | G01R 1/073 |
· · · · | Multiple probes [3]

|  | G01R 1/08 |
· · | Pointers; Scales, Scale illumination

|  | G01R 1/10 |
· · | Arrangements of bearings

|  | G01R 1/12 |
· · · | of strip or wire bearings

|  | G01R 1/14 |
· · | Braking arrangements; Damping arrangements

|  | G01R 1/16 |
· · | Magnets

|  | G01R 1/18 |
· · | Screening arrangements against electric or magnetic fields, e.g. against earth's field

|  | G01R 1/20 |
· | Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments

|  | G01R 1/22 |
· · | Tong testers acting as secondary windings of current transformers (voltage or current isolation using transformers Fulltext... Hierarchy... Expanded...G01R 15/18)

|  | G01R 1/24 |
· · | Transmission-line, e.g. waveguide, measuring sections, e.g. slotted section

|  | G01R 1/26 |
· · · | with linear movement of probe

|  | G01R 1/28 |
· | Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform

|  | G01R 1/30 |
· | Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier

|  | G01R 1/36 |
· | Overload-protection arrangements or circuits for electric measuring instruments

|  | G01R 1/38 |
· | Arrangements for altering the indicating characteristic, e.g. by modifying the air gap (circuits Fulltext... Hierarchy... Expanded...G01D 3/02)

|  | G01R 1/40 |
· | Modifications of instruments to indicate the maximum or the minimum value reached in a time interval, e.g. by maximum indicator pointer [3]

|  | G01R 1/42 |
· · | thermally operated

|  | G01R 1/44 |
· | Modifications of instruments for temperature compensation [2]

P:180 |  | G01R 3/00 |
Apparatus or processes specially adapted for the manufacture of measuring instruments

P:60 |  | G01R 5/00 |
Instruments for converting a single current or a single voltage into a mechanical displacement (vibration galvanometers Fulltext... Hierarchy... Expanded...G01R 9/02)

|  | G01R 5/02 |
· | Moving-coil instruments

|  | G01R 5/04 |
· · | with magnet external to the coil

|  | G01R 5/06 |
· · | with core magnet

|  | G01R 5/08 |
· · | specially adapted for wide angle deflection; with eccentrically-pivoted moving coil

|  | G01R 5/10 |
· | String galvanometers

|  | G01R 5/12 |
· | Loop galvanometers

|  | G01R 5/14 |
· | Moving-iron instruments

|  | G01R 5/16 |
· · | with pivoting magnet

|  | G01R 5/18 |
· · | with pivoting soft iron, e.g. needle galvanometer

|  | G01R 5/20 |
· | Induction instruments e.g. Ferraris instruments

|  | G01R 5/22 |
· | Thermoelectric instruments (measuring effective values of currents or voltages using thermoconverters Fulltext... Hierarchy... Expanded...G01R 19/03)

|  | G01R 5/24 |
· · | operated by elongation of a strip or wire or by expansion of a gas or fluid

|  | G01R 5/26 |
· · | operated by deformation of a bimetallic element

|  | G01R 5/28 |
· | Electrostatic instruments (combined with radiation detector Fulltext... Hierarchy... Expanded...G01T)

|  | G01R 5/30 |
· · | Leaf electrometers

|  | G01R 5/32 |
· · | Wire electrometers; Needle electrometers

|  | G01R 5/34 |
· · | Quadrant electrometers

P:50 |  | G01R 7/00 |
Instruments capable of converting two or more currents or voltages into a single mechanical displacement (Fulltext... Hierarchy... Expanded...G01R 9/00 takes precedence)

|  | G01R 7/02 |
· | for forming a sum or a difference

|  | G01R 7/04 |
· | for forming a quotient (for measuring resistance Fulltext... Hierarchy... Expanded...G01R 27/08)

|  | G01R 7/06 |
· · | moving-iron type

|  | G01R 7/08 |
· · | moving-coil type, e.g. crossed-coil type

|  | G01R 7/10 |
· · · | having more than two moving coils

|  | G01R 7/12 |
· | for forming product

|  | G01R 7/14 |
· · | moving-iron type

|  | G01R 7/16 |
· · | having both fixed and moving coils, i.e. dynamometers

|  | G01R 7/18 |
· · · | with iron core magnetically coupling fixed and moving coils

P:40 |  | G01R 9/00 |
Instruments employing mechanical resonance

|  | G01R 9/02 |
· | Vibration galvanometers, e.g. for measuring current

|  | G01R 9/04 |
· | using vibrating reeds, e.g. for measuring frequency

|  | G01R 9/06 |
· · | magnetically driven

|  | G01R 9/08 |
· · | piezo-electrically driven

P:30 |  | G01R 11/00 |
Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption (monitoring electric consumption of electrically-propelled vehicles Fulltext... Hierarchy... Expanded...B60L 3/00)

|  | G01R 11/02 |
· | Constructional details (applicable to electric measuring instruments in general Fulltext... Hierarchy... Expanded...G01R 1/00)

|  | G01R 11/04 |
· · | Housings; Supporting racks; Arrangements of terminals

|  | G01R 11/06 |
· · | Magnetic circuits of induction meters [2]

|  | G01R 11/067 |
· · · | Coils therefor [2]

|  | G01R 11/073 |
· · · | Armatures therefor [2]

|  | G01R 11/09 |
· · · · | Disc armatures [2]

|  | G01R 11/10 |
· · | Braking magnets; Damping arrangements

|  | G01R 11/12 |
· · | Arrangements of bearings

|  | G01R 11/14 |
· · · | with magnetic relief

|  | G01R 11/16 |
· · | Adaptations of counters to electricity meters

|  | G01R 11/17 |
· · | Compensating for errors; Adjusting or regulating means therefor [2]

|  | G01R 11/18 |
· · · | Compensating for variations in ambient conditions [2]

|  | G01R 11/185 |
· · · · | Temperature compensation [2]

|  | G01R 11/19 |
· · · | Compensating for errors caused by disturbing torque, e.g. rotating-field errors of polyphase meters [2]

|  | G01R 11/20 |
· · · | Compensating for phase errors in induction meters [2]

|  | G01R 11/21 |
· · · | Compensating for errors caused by damping effects of the current, e.g. adjustment in the overload range [2]

|  | G01R 11/22 |
· · · | Adjusting torque, e.g. adjusting starting torque, adjusting of polyphase meters for obtaining equal torques [2]

|  | G01R 11/23 |
· · · | Compensating for errors caused by friction, e.g. adjustment in the light-load range [2]

|  | G01R 11/24 |
· · | Arrangements for avoiding or indicating fraudulent use [4]

|  | G01R 11/25 |
· · | Arrangements for indicating or signalling faults [2,4]

|  | G01R 11/30 - G01R 11/46 |
Note(s) Groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 11/48-G01R 11/56 take precedence over groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 11/30-G01R 11/46. [4]

|  | G01R 11/30 |
· | Dynamo-electric motor meters

|  | G01R 11/32 |
· · | Watt-hour meters

|  | G01R 11/34 |
· · | Ampère-hour meters

|  | G01R 11/36 |
· | Induction meters, e.g. Ferraris meters (Ferraris instruments Fulltext... Hierarchy... Expanded...G01R 5/20)

|  | G01R 11/38 |
· · | for single-phase operation

|  | G01R 11/40 |
· · | for polyphase operation

|  | G01R 11/42 |
· · · | Circuitry therefor

|  | G01R 11/46 |
· | Electrically-operated clockwork meters; Oscillatory meters; Pendulum meters

|  | G01R 11/48 |
· | Meters specially adapted for measuring real or reactive components; Meters specially adapted for measuring apparent energy

|  | G01R 11/50 |
· · | for measuring real component

|  | G01R 11/52 |
· · | for measuring reactive component

|  | G01R 11/54 |
· · | for measuring simultaneously at least two of the following three variables: real component, reactive component, apparent energy

|  | G01R 11/56 |
· | Special tariff meters

|  | G01R 11/57 |
· · | Multi-rate meters (Fulltext... Hierarchy... Expanded...G01R 11/63 takes precedence) [2]

|  | G01R 11/58 |
· · · | Tariff-switching devices therefor [2]

|  | G01R 11/60 |
· · | Subtraction meters; Meters measuring maximum or minimum-load hours

|  | G01R 11/63 |
· · | Over-consumption meters, e.g. measuring consumption while a predetermined level of power is exceeded [2]

|  | G01R 11/64 |
· · | Maximum meters, e.g. tariff for a period is based on maximum demand within that period

|  | G01R 11/66 |
· · · | Circuitry

P:70 |  | G01R 13/00 |
Arrangements for displaying electric variables or waveformes (display by mechanical displacement only Fulltext... Hierarchy... Expanded...G01R 5/00, Fulltext... Hierarchy... Expanded...G01R 7/00, Fulltext... Hierarchy... Expanded...G01R 9/00; recording frequency spectrum Fulltext... Hierarchy... Expanded...G01R 23/18) [4]

|  | G01R 13/02 |
· | for displaying measured electric variables in digital form (counters Fulltext... Hierarchy... Expanded...G06M; analogue/digital conversion in general Fulltext... Hierarchy... Expanded...H03M 1/00) [4]

|  | G01R 13/04 |
· | for producing permanent records [4]

|  | G01R 13/06 |
· · | Modifications for recording transient disturbances, e.g. by starting or accelerating a recording medium

|  | G01R 13/08 |
· · | Electromechanical recording system using a mechanical direct-writing method

|  | G01R 13/10 |
· · · | with intermittent recording by representing the variable by the length of a stroke or by the position of a dot

|  | G01R 13/12 |
· · | Chemical recording, e.g. clydonographs (Fulltext... Hierarchy... Expanded...G01R 13/14 takes precedence)

|  | G01R 13/14 |
· · | Recording on a light-sensitive material

|  | G01R 13/16 |
· · | Recording on a magnetic medium

|  | G01R 13/18 |
· · · | using boundary displacement

|  | G01R 13/20 |
· | Cathode-ray oscilloscopes (cathode-ray tubes Fulltext... Hierarchy... Expanded...H01J 31/00)

|  | G01R 13/22 |
· · | Circuits therefor (circuits for generating pulses, e.g. sawtooth waveforms Fulltext... Hierarchy... Expanded...H03K 3/00)

|  | G01R 13/24 |
· · · | Time-base deflection circuits

|  | G01R 13/26 |
· · · | Circuits for controlling the intensity of the electron beam (brilliance control Fulltext... Hierarchy... Expanded...H01J 29/98)

|  | G01R 13/28 |
· · · | Circuits for simultaneous or sequential presentation of more than one variable (electronic switches Fulltext... Hierarchy... Expanded...H03K 17/00)

|  | G01R 13/30 |
· · · | Circuits for inserting reference markers, e.g. for timing, for calibrating, for frequency marking

|  | G01R 13/32 |
· · · | Circuits for displaying non-recurrent functions such as transients; Circuits for triggering; Circuits for synchronisation; Circuits for time-base expansion

|  | G01R 13/34 |
· · · | Circuits for representing a single waveform by sampling, e.g. for very high frequencies (sample-and-hold arrangements Fulltext... Hierarchy... Expanded...G11C 27/02) [2]

|  | G01R 13/36 |
· | using length of glow discharge, e.g. glowlight oscilloscopes (discharge tubes Fulltext... Hierarchy... Expanded...H01J) [4]

|  | G01R 13/38 |
· | using the steady or oscillatory displacement of a light beam by an electromechanical measuring system (such measuring systems per se Fulltext... Hierarchy... Expanded...G01R 5/00, Fulltext... Hierarchy... Expanded...G01R 7/00, Fulltext... Hierarchy... Expanded...G01R 9/00) [4]

|  | G01R 13/40 |
· | using modulation of a light beam otherwise than by mechanical displacement, e.g. by Kerr effect [4]

|  | G01R 13/42 |
· | Instruments using length of spark discharge, e.g. by measuring maximum separation of electrodes to produce spark

P:170 |  | G01R 15/00 |
Details of measuring arrangements of the types provided for in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 17/00-G01R 29/00, Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 33/00-G01R 33/26 and Fulltext... Hierarchy... Expanded...G01R 35/00 (details of instruments Fulltext... Hierarchy... Expanded...G01R 1/00; measuring leads, measuring probes Fulltext... Hierarchy... Expanded...G01R 1/06; overload protection arrangements Fulltext... Hierarchy... Expanded...G01R 1/36; circuits for correcting the transfer function Fulltext... Hierarchy... Expanded...G01D 3/02) [1,8]

|  | G01R 15/04 |
· | Voltage dividers [6]

|  | G01R 15/06 |
· · | having reactive components, e.g. capacitive transformer [6]

|  | G01R 15/08 |
· | Circuits for altering the measuring range

|  | G01R 15/09 |
· · | Autoranging circuits [6]

|  | G01R 15/12 |
· | Circuits for multi-testers, e.g. for measuring voltage, current, or impedance at will

|  | G01R 15/14 |
· | Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks (voltage dividers Fulltext... Hierarchy... Expanded...G01R 15/04) [6]

|  | G01R 15/16 |
· · | using capacitive devices [6]

|  | G01R 15/18 |
· · | using inductive devices, e.g. transformers [6]

|  | G01R 15/20 |
· · | using galvano-magnetic devices, e.g. Hall-effect devices [6]

|  | G01R 15/22 |
· · | using light-emitting devices, e.g. LED, optocouplers [6]

|  | G01R 15/24 |
· · | using light-modulating devices [6]

|  | G01R 15/26 |
· · | using modulation of waves other than light, e.g. radio or acoustic waves [6]

P:90 |  | G01R 17/00 |
Measuring arrangements involving comparison with a reference value, e.g. bridge

|  | G01R 17/02 |
· | Arrangements in which the value to be measured is automatically compared with a reference value

|  | G01R 17/04 |
· · | in which the reference value is continuously or periodically swept over the range of values to be measured

|  | G01R 17/06 |
· · | Automatic balancing arrangements

|  | G01R 17/08 |
· · · | in which a force or torque representing the measured value is balanced by a force or torque representing the reference value

|  | G01R 17/10 |
· | ac or dc measuring bridges (automatic comparison or re-balancing arrangements Fulltext... Hierarchy... Expanded...G01R 17/02)

|  | G01R 17/12 |
· · | using comparison of currents, e.g. bridges with differential current output

|  | G01R 17/14 |
· · | with indication of measured value by calibrated null indicator, e.g. percent bridge, tolerance bridge (Fulltext... Hierarchy... Expanded...G01R 17/12, Fulltext... Hierarchy... Expanded...G01R 17/16 take precedence)

|  | G01R 17/16 |
· · | with discharge tubes or semiconductor devices in one or more arms of the bridge, e.g. voltmeter using a difference amplifier

|  | G01R 17/18 |
· · | with more than four branches

|  | G01R 17/20 |
· | ac or dc potentiometric measuring arrangements (automatic comparison or re-balancing arrangements Fulltext... Hierarchy... Expanded...G01R 17/02)

|  | G01R 17/22 |
· · | with indication of measured value by calibrated null indicator

P:120 |  | G01R 19/00 |
Arrangements for measuring currents or voltages or for indicating presence or sign thereof (Fulltext... Hierarchy... Expanded...G01R 5/00 takes precedence; for measuring bioelectric currents or voltages Fulltext... Hierarchy... Expanded...A61B 5/04) [4]

|  | G01R 19/02 - G01R 19/32 |
Note(s) Within groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 19/02-G01R 19/32, group Fulltext... Hierarchy... Expanded...G01R 19/28 takes precedence. Groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 19/18-G01R 19/25 take precedence over groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 19/02-G01R 19/165 and Fulltext... Hierarchy... Expanded...G01R 19/30. [3]

|  | G01R 19/02 |
· | Measuring effective values, i.e. root-mean-square values

|  | G01R 19/03 |
· · | using thermoconverters [4]

|  | G01R 19/04 |
· | Measuring peak values of ac or of pulses [2]

|  | G01R 19/06 |
· | Measuring real component; Measuring reactive component

|  | G01R 19/08 |
· | Measuring current density

|  | G01R 19/10 |
· | Measuring sum, difference, or ratio

|  | G01R 19/12 |
· | Measuring rate of change

|  | G01R 19/14 |
· | Indicating direction of current; Indicating polarity of voltage

|  | G01R 19/145 |
· | Indicating the presence of current or voltage [3]

|  | G01R 19/15 |
· · | Indicating the presence of current [3]

|  | G01R 19/155 |
· · | Indicating the presence of voltage [3]

|  | G01R 19/165 |
· | Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values (circuits with regenerative action, e.g. Schmitt trigger Fulltext... Hierarchy... Expanded...H03K 3/00; threshold switches Fulltext... Hierarchy... Expanded...H03K 17/00) [3]

|  | G01R 19/17 |
· · | giving an indication of the number of times this occurs [3]

|  | G01R 19/175 |
· | Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero [3]

|  | G01R 19/18 |
· | using conversion of dc into ac, e.g. with choppers

|  | G01R 19/20 |
· · | using transductors

|  | G01R 19/22 |
· | using conversion of ac into dc

|  | G01R 19/25 |
· | using digital measurement techniques (arrangements for displaying measured electric variables in digital form Fulltext... Hierarchy... Expanded...G01R 13/02) [3]

|  | G01R 19/252 |
· · | using analogue/digital converters of the type with conversion of voltage or current into frequency and measuring of this frequency [4]

|  | G01R 19/255 |
· · | using analogue/digital converters of the type with counting of pulses during a period of time proportional to voltage or current, delivered by a pulse generator with fixed frequency [4]

|  | G01R 19/257 |
· · | using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method [4]

|  | G01R 19/28 |
· | adapted for measuring in circuits having distributed constants

|  | G01R 19/30 |
· | Measuring the maximum or the minimum value of current or voltage reached in a time interval (Fulltext... Hierarchy... Expanded...G01R 19/04 takes precedence; modifications of instruments to indicate the maximum or the minimum value reached in a time interval Fulltext... Hierarchy... Expanded...G01R 1/40) [2,3]

|  | G01R 19/32 |
· | Compensating for temperature change (modifications of instruments for temperature compensation Fulltext... Hierarchy... Expanded...G01R 1/44) [2]

P:100 |  | G01R 21/00 |
Arrangements for measuring electric power or power factor (Fulltext... Hierarchy... Expanded...G01R 7/12 takes precedence) [4]

|  | G01R 21/01 |
· | in circuits having distributed constants (Fulltext... Hierarchy... Expanded...G01R 21/04, Fulltext... Hierarchy... Expanded...G01R 21/07, Fulltext... Hierarchy... Expanded...G01R 21/09, Fulltext... Hierarchy... Expanded...G01R 21/12 take precedence) [2]

|  | G01R 21/02 |
· | by thermal methods [2]

|  | G01R 21/04 |
· · | in circuits having distributed constants

|  | G01R 21/06 |
· | by measuring current and voltage (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 21/08-G01R 21/133 take precedence) [4]

|  | G01R 21/07 |
· · | in circuits having distributed constants (Fulltext... Hierarchy... Expanded...G01R 21/09 takes precedence) [2]

|  | G01R 21/08 |
· | by using galvanomagnetic-effect devices, e.g. Hall-effect devices (such devices per se Fulltext... Hierarchy... Expanded...H01L) [2]

|  | G01R 21/09 |
· · | in circuits having distributed constants [2]

|  | G01R 21/10 |
· | by using square-law characteristics of circuit elements, e.g. diodes, to measure power absorbed by loads of known impedance (Fulltext... Hierarchy... Expanded...G01R 21/02 takes precedence) [2]

|  | G01R 21/12 |
· · | in circuits having distributed constants

|  | G01R 21/127 |
· | by using pulse modulation (Fulltext... Hierarchy... Expanded...G01R 21/133 takes precedence) [4]

|  | G01R 21/133 |
· | by using digital technique [4]

|  | G01R 21/14 |
· | Compensating for temperature change [2]

P:110 |  | G01R 22/00 |
Arrangements for measuring time integral of electric power or current, e.g. electricity meters (electromechanical arrangements therefor Fulltext... Hierarchy... Expanded...G01R 11/00; monitoring electric consumption of electrically-propelled vehicles Fulltext... Hierarchy... Expanded...B60L 3/00) [4,8]

|  | G01R 22/00 |
Note(s) An arrangement for measuring time integral of electric power is classified in group Fulltext... Hierarchy... Expanded...G01R 21/00 if the essential characteristic is the measuring of electric power. [4]

|  | G01R 22/02 |
· | by electrolytic methods [4]

|  | G01R 22/04 |
· | by calorimetric methods [4]

|  | G01R 22/06 |
· | by electronic methods [8]

|  | G01R 22/08 |
· · | using analogue techniques [8]

|  | G01R 22/10 |
· · | using digital techniques [8]

P:130 |  | G01R 23/00 |
Arrangements for measuring frequencies; Arrangements for analysing frequency spectra (frequency discriminators Fulltext... Hierarchy... Expanded...H03D)

|  | G01R 23/02 |
· | Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage (measuring short time intervals Fulltext... Hierarchy... Expanded...G04F)

|  | G01R 23/04 |
· · | adapted for measuring in circuits having distributed constants

|  | G01R 23/06 |
· · | by converting frequency into an amplitude of current or voltage

|  | G01R 23/07 |
· · · | using response of circuits tuned on resonance, e.g. grid-drip meter [2]

|  | G01R 23/08 |
· · · | using response of circuits tuned off resonance

|  | G01R 23/09 |
· · · | using analogue integrators, e.g. capacitors establishing a mean value by balance of input signals and defined discharge signals or leakage (radiation-measuring instruments in which pulses generated by a radiation detector are integrated Fulltext... Hierarchy... Expanded...G01T 1/15) [2]

|  | G01R 23/10 |
· · | by converting frequency into a train of pulses, which are then counted

|  | G01R 23/12 |
· · | by converting frequency into phase shift

|  | G01R 23/14 |
· · | by heterodyning; by beat-frequency comparison (generation of oscillations by beating unmodulated signals of different frequencies Fulltext... Hierarchy... Expanded...H03B 21/00) [2]

|  | G01R 23/15 |
· · | Indicating that frequency of pulses is either above or below a predetermined value or within or outside a predetermined range of values, by making use of non-linear or digital elements [3]

|  | G01R 23/16 |
· | Spectrum analysis; Fourier analysis

|  | G01R 23/163 |
· · | adapted for measuring in circuits having distributed constants [3]

|  | G01R 23/165 |
· · | using filters [3]

|  | G01R 23/167 |
· · · | with digital filters [3]

|  | G01R 23/17 |
· · | with optical auxiliary devices [3]

|  | G01R 23/173 |
· · | Wobbulating devices similar to swept panoramic receivers (panoramic receivers per se Fulltext... Hierarchy... Expanded...H03J 7/32) [3]

|  | G01R 23/175 |
· · | by delay means, e.g. tapped delay lines [3]

|  | G01R 23/177 |
· · | Analysis of very low frequencies [3]

|  | G01R 23/18 |
· · | with provision for recording frequency spectrum

|  | G01R 23/20 |
· · | Measurement of non-linear distortion

P:140 |  | G01R 25/00 |
Arrangements for measuring phase angle between a voltage and a current or between voltages or currents (measuring power factor Fulltext... Hierarchy... Expanded...G01R 21/00; measuring position of individual pulses in a pulse train Fulltext... Hierarchy... Expanded...G01R 29/02; phase discriminators Fulltext... Hierarchy... Expanded...H03D) [2]

|  | G01R 25/02 |
· | in circuits having distributed constants

|  | G01R 25/04 |
· | involving adjustment of a phase shifter to produce a predetermined phase difference, e.g. zero difference

|  | G01R 25/06 |
· | employing quotient instrument

|  | G01R 25/08 |
· | by counting of standard pulses (measuring time intervals Fulltext... Hierarchy... Expanded...G04F) [2]

P:150 |  | G01R 27/00 |
Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom

|  | G01R 27/02 |
· | Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only Fulltext... Hierarchy... Expanded...G01R 25/00)

|  | G01R 27/04 |
· · | in circuits having distributed constants

|  | G01R 27/06 |
· · · | Measuring reflection coefficients; Measuring standing-wave ratio

|  | G01R 27/08 |
· · | Measuring resistance by measuring both voltage and current

|  | G01R 27/10 |
· · · | using two-coil or crossed-coil instruments forming quotient

|  | G01R 27/12 |
· · · · | using hand generators, e.g. meggers

|  | G01R 27/14 |
· · | Measuring resistance by measuring current or voltage obtained from a reference source (Fulltext... Hierarchy... Expanded...G01R 27/16, Fulltext... Hierarchy... Expanded...G01R 27/20, Fulltext... Hierarchy... Expanded...G01R 27/22 take precedence)

|  | G01R 27/16 |
· · | Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line

|  | G01R 27/18 |
· · · | Measuring resistance to earth

|  | G01R 27/20 |
· · | Measuring earth resistance; Measuring contact resistance of earth connections, e.g. plates

|  | G01R 27/22 |
· · | Measuring resistance of fluids (measuring vessels, electrodes therefor Fulltext... Hierarchy... Expanded...G01N 27/07)

|  | G01R 27/26 |
· · | Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants

|  | G01R 27/28 |
· | Measuring attenuation, gain, phase shift, or derived characteristics of electric four-pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems Fulltext... Hierarchy... Expanded...H04B 3/46)

|  | G01R 27/30 |
· · | with provision for recording characteristics, e.g. by plotting Nyquist diagram

|  | G01R 27/32 |
· · | in circuits having distributed constants [2]

P:160 |  | G01R 29/00 |
Arrangements for measuring or indicating electric quantities not covered by groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 19/00-G01R 27/00

|  | G01R 29/02 |
· | Measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time, duration (of amplitude Fulltext... Hierarchy... Expanded...G01R 19/00; of repetition rate Fulltext... Hierarchy... Expanded...G01R 23/00; of phase difference of two cyclic pulse trains Fulltext... Hierarchy... Expanded...G01R 25/00; monitoring pattern of pulse trains Fulltext... Hierarchy... Expanded...H03K 5/19) [3]

|  | G01R 29/027 |
· · | Indicating that a pulse characteristic is either above or below a predetermined value or within or beyond a predetermined range of values [3]

|  | G01R 29/033 |
· · · | giving an indication of the number of times this occurs [3]

|  | G01R 29/04 |
· | Measuring form factor, i.e. quotient of root-mean-square value and arithmetic mean of instantaneous value; Measuring peak factor, i.e. quotient of maximum value and root-mean-square value

|  | G01R 29/06 |
· | Measuring depth of modulation

|  | G01R 29/08 |
· | Measuring electromagnetic field characteristics

|  | G01R 29/10 |
· · | Radiation diagrams of aerials

|  | G01R 29/12 |
· | Measuring electrostatic fields

|  | G01R 29/14 |
· · | Measuring field distribution

|  | G01R 29/16 |
· | Measuring asymmetry of polyphase networks

|  | G01R 29/18 |
· | Indicating phase sequence; Indicating synchronism

|  | G01R 29/20 |
· | Measuring number of turns; Measuring transformation ratio or coupling factor of windings (calibrating instrument transformers Fulltext... Hierarchy... Expanded...G01R 35/02)

|  | G01R 29/22 |
· | Measuring piezo-electric properties

|  | G01R 29/24 |
· | Arrangements for measuring quantities of charge (electrostatic instruments Fulltext... Hierarchy... Expanded...G01R 5/28; indicating presence of current Fulltext... Hierarchy... Expanded...G01R 19/15; arrangements for measuring time integral of electric power or current Fulltext... Hierarchy... Expanded...G01R 22/00) [2]

|  | G01R 29/26 |
· | Measuring noise figure; Measuring signal-to-noise ratio [2]

P:10 |  | G01R 31/00 |
Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere (measuring leads, measuring probes Fulltext... Hierarchy... Expanded...G01R 1/06; indicating electrical condition of switchgear or protective devices Fulltext... Hierarchy... Expanded...H01H 71/04, Fulltext... Hierarchy... Expanded...H01H 73/12, Fulltext... Hierarchy... Expanded...H02B 11/10, Fulltext... Hierarchy... Expanded...H02H 3/04; testing or measuring semiconductors or solid state devices during manufacture Fulltext... Hierarchy... Expanded...H01L 21/66; testing line transmission systems Fulltext... Hierarchy... Expanded...H04B 3/46)

|  | G01R 31/01 |
· | Subjecting similar articles in turn to test, e.g. "go/no-go" tests in mass production; Testing objects at points as they pass through a testing station (Fulltext... Hierarchy... Expanded...G01R 31/18 takes precedence) [6]

|  | G01R 31/02 |
· | Testing of electric apparatus, lines, or components for short-circuits, discontinuities, leakage, or incorrect line connection

|  | G01R 31/04 |
· · | Testing connections, e.g. of plugs, of non-disconnectable joints

|  | G01R 31/06 |
· · | Testing of electric windings, e.g. for polarity (measuring number of turns, transformation ratio, or coupling factor Fulltext... Hierarchy... Expanded...G01R 29/20)

|  | G01R 31/07 |
· · | Testing of fuses (means for indicating condition of fuse structurally associated with the fuse Fulltext... Hierarchy... Expanded...H01H 85/30) [6]

|  | G01R 31/08 |
· | Locating faults in cables, transmission lines, or networks (emergency protective circuit arrangements Fulltext... Hierarchy... Expanded...H02H)

|  | G01R 31/10 |
· · | by increasing destruction at fault, e.g. burning-in by using a pulse generator operating a special programme

|  | G01R 31/11 |
· · | using pulse-reflection methods

|  | G01R 31/12 |
· | Testing dielectric strength or breakdown voltage

|  | G01R 31/14 |
· · | Circuits therefor

|  | G01R 31/16 |
· · | Construction of testing vessels; Electrodes therefor

|  | G01R 31/18 |
· · | Subjecting similar articles in turn to test, e.g. "go/no-go" tests in mass production

|  | G01R 31/20 |
· · | Preparation of articles or specimens to facilitate testing

|  | G01R 31/24 |
· | Testing of discharge tubes (during manufacture Fulltext... Hierarchy... Expanded...H01J 9/42) [2]

|  | G01R 31/25 |
· · | Testing of vacuum tubes [2]

|  | G01R 31/26 |
· | Testing of individual semiconductor devices (measurement of impurity content of materials Fulltext... Hierarchy... Expanded...G01N) [2]

|  | G01R 31/265 |
· · | Contactless testing [6]

|  | G01R 31/27 |
· · | Testing of devices without physical removal from the circuit of which they form part, e.g. compensating for effects due to surrounding elements [6]

|  | G01R 31/28 |
· | Testing of electronic circuits, e.g. by signal tracer (testing for short-circuits, discontinuities, leakage or incorrect line connection Fulltext... Hierarchy... Expanded...G01R 31/02; checking computers Fulltext... Hierarchy... Expanded...G06F 11/00; checking static stores for correct operation or testing static stores during standby or offline operation Fulltext... Hierarchy... Expanded...G11C 29/00)

|  | G01R 31/30 |
· · | Marginal testing, e.g. by varying supply voltage (marginal testing of computers Fulltext... Hierarchy... Expanded...G06) [2]

|  | G01R 31/302 |
· · | Contactless testing (non contact-making probes Fulltext... Hierarchy... Expanded...G01R 1/07) [5]

|  | G01R 31/303 |
· · · | of integrated circuits (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 31/305-G01R 31/315 take precedence) [6]

|  | G01R 31/304 |
· · · | of printed or hybrid circuits (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 31/305-G01R 31/315 take precedence) [6]

|  | G01R 31/305 |
· · · | using electron beams [5]

|  | G01R 31/306 |
· · · · | of printed or hybrid circuits [6]

|  | G01R 31/307 |
· · · · | of integrated circuits [6]

|  | G01R 31/308 |
· · · | using non-ionising electromagnetic radiation, e.g. optical radiation [5]

|  | G01R 31/309 |
· · · · | of printed or hybrid circuits [6]

|  | G01R 31/311 |
· · · · | of integrated circuits [6]

|  | G01R 31/312 |
· · · | by capacitive methods [5]

|  | G01R 31/315 |
· · · | by inductive methods [5]

|  | G01R 31/316 |
· · | Testing of analog circuits [6]

|  | G01R 31/3161 |
· · · | Marginal testing [6]

|  | G01R 31/3163 |
· · · | Functional testing [6]

|  | G01R 31/3167 |
· · | Testing of combined analog and digital circuits [6]

|  | G01R 31/317 |
· · | Testing of digital circuits [6]

|  | G01R 31/3173 |
· · · | Marginal testing [6]

|  | G01R 31/3177 |
· · · | Testing of logic operation, e.g. by logic analysers [6]

|  | G01R 31/3181 |
· · · | Functional testing (Fulltext... Hierarchy... Expanded...G01R 31/3177 takes precedence) [6]

|  | G01R 31/3183 |
· · · · | Generation of test inputs, e.g. test vectors, patterns or sequences [6]

|  | G01R 31/3185 |
· · · · | Reconfiguring for testing, e.g. LSSD, partitioning [6]

|  | G01R 31/3187 |
· · · · | Built-in tests [6]

|  | G01R 31/319 |
· · · · | Tester hardware, i.e. output processing circuits [6]

|  | G01R 31/3193 |
· · · · · | with comparison between actual response and known fault-free response [6]

|  | G01R 31/327 |
· | Testing of circuit interrupters, switches or circuit-breakers (structural association with switches Fulltext... Hierarchy... Expanded...H01H) [6]

|  | G01R 31/333 |
· · | Testing of the switching capacity of high-voltage circuit-breakers (means for detecting the presence of an arc or discharge in switching devices Fulltext... Hierarchy... Expanded...H01H 9/50, Fulltext... Hierarchy... Expanded...H01H 33/26) [6]

|  | G01R 31/34 |
· | Testing dynamo-electric machines (testing electric windings Fulltext... Hierarchy... Expanded...G01R 31/06; methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing dynamo-electric machines Fulltext... Hierarchy... Expanded...H02K 15/00) [3]

|  | G01R 31/36 |
· | Apparatus for testing electrical condition of accumulators or electric batteries, e.g. capacity or charge condition (accumulators combined with arrangements for measuring, testing or indicating condition Fulltext... Hierarchy... Expanded...H01M 10/48; circuit arrangements for charging, or depolarising batteries or for supplying loads from batteries Fulltext... Hierarchy... Expanded...H02J 7/00) [3]

|  | G01R 31/38 |
· | Testing of sparking-plugs (testing non-electrical properties Fulltext... Hierarchy... Expanded...G01M 19/02) [6]

|  | G01R 31/40 |
· | Testing power supplies [6]

|  | G01R 31/42 |
· · | AC power supplies [6]

|  | G01R 31/44 |
· | Testing lamps (discharge lamps Fulltext... Hierarchy... Expanded...G01R 31/24; structurally associated with light source circuit arrangements for detecting lamp failure Fulltext... Hierarchy... Expanded...H05B 37/03) [6]

P:20 |  | G01R 33/00 |
Arrangements or instruments for measuring magnetic variables

|  | G01R 33/02 |
· | Measuring direction or magnitude of magnetic fields or magnetic flux (Fulltext... Hierarchy... Expanded...G01R 33/20 takes precedence; measuring direction or magnitude of the earth's field for navigation or surveying Fulltext... Hierarchy... Expanded...G01C; for prospecting, for measuring the magnetic field of the earth Fulltext... Hierarchy... Expanded...G01V 3/00) [4]

|  | G01R 33/022 |
· · | Measuring gradient [3]

|  | G01R 33/025 - G01R 33/06 |
Note(s) Group Fulltext... Hierarchy... Expanded...G01R 33/022 or group Fulltext... Hierarchy... Expanded...G01R 33/10 takes precedence over groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 33/025-G01R 33/06.

|  | G01R 33/025 |
· · | Compensating stray fields [3]

|  | G01R 33/028 |
· · | Electrodynamic magnetometers [3]

|  | G01R 33/032 |
· · | using magneto-optic devices, e.g. Faraday [3]

|  | G01R 33/035 |
· · | using superconductive devices [3]

|  | G01R 33/038 |
· · | using permanent magnets, e.g. balances, torsion devices [3]

|  | G01R 33/04 |
· · | using the flux-gate principle

|  | G01R 33/05 |
· · · | in thin-film element [3]

|  | G01R 33/06 |
· · | using galvano-magnetic devices

|  | G01R 33/07 |
· · · | Hall-effect devices [6]

|  | G01R 33/09 |
· · · | Magneto-resistive devices [6]

|  | G01R 33/10 |
· · | Plotting field distribution

|  | G01R 33/12 |
· | Measuring magnetic properties of articles or specimens of solids or fluids (involving magnetic resonance Fulltext... Hierarchy... Expanded...G01R 33/20) [4]

|  | G01R 33/14 |
· · | Measuring or plotting hysteresis curves

|  | G01R 33/16 |
· · | Measuring susceptibility

|  | G01R 33/18 |
· · | Measuring magnetostrictive properties

|  | G01R 33/20 |
· | involving magnetic resonance (medical aspects Fulltext... Hierarchy... Expanded...A61B 5/055; magnetic resonance gyrometers Fulltext... Hierarchy... Expanded...G01C 19/60) [4,5]

|  | G01R 33/24 |
· · | for measuring direction or magnitude of magnetic fields or magnetic flux [4]

|  | G01R 33/26 |
· · · | using optical pumping [4]

|  | G01R 33/28 |
· · | Details of apparatus provided for in groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 33/44-G01R 33/64 [5]

|  | G01R 33/30 |
· · · | Sample handling arrangements, e.g. sample cells, spinning mechanisms [5]

|  | G01R 33/31 |
· · · · | Temperature control thereof [6]

|  | G01R 33/32 |
· · · | Excitation or detection systems, e.g. using radiofrequency signals [5]

|  | G01R 33/34 |
· · · · | Constructional details, e.g. resonators [5]

|  | G01R 33/341 |
· · · · · | comprising surface coils [6]

|  | G01R 33/3415 |
· · · · · · | comprising arrays of sub-coils [6]

|  | G01R 33/343 |
· · · · · | of slotted-tube or loop-gap type [6]

|  | G01R 33/345 |
· · · · · | of waveguide type (Fulltext... Hierarchy... Expanded...G01R 33/343 takes precedence) [6]

|  | G01R 33/36 |
· · · · | Electrical details, e.g. matching or coupling of the coil to the receiver [5]

|  | G01R 33/38 |
· · · | Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field [5]

|  | G01R 33/381 - G01R 33/383 |
Note(s) Groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 33/385-G01R 33/389 take precedence over groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G01R 33/381-G01R 33/383. [6]

|  | G01R 33/381 |
· · · · | using electromagnets (electromagnets per se Fulltext... Hierarchy... Expanded...H01F 7/06) [6]

|  | G01R 33/3815 |
· · · · · | with superconducting coils, e.g. power supply therefor (superconductive magnets Fulltext... Hierarchy... Expanded...H01F 6/00) [6]

|  | G01R 33/383 |
· · · · | using permanent magnets (permanent magnets per se Fulltext... Hierarchy... Expanded...H01F 7/02) [6]

|  | G01R 33/385 |
· · · · | using gradient magnetic field coils [6]

|  | G01R 33/387 |
· · · · | Compensation of inhomogeneities (screening Fulltext... Hierarchy... Expanded...G01R 33/42) [6]

|  | G01R 33/3873 |
· · · · · | using ferromagnetic bodies [6]

|  | G01R 33/3875 |
· · · · · | using correction coil assemblies, e.g. active shimming [6]

|  | G01R 33/389 |
· · · · | Field stabilisation [6]

|  | G01R 33/42 |
· · · | Screening (screening in general Fulltext... Hierarchy... Expanded...H05K 9/00) [5,6]

|  | G01R 33/421 |
· · · · | of main or gradient magnetic field [6]

|  | G01R 33/422 |
· · · · | of the radiofrequency field [6]

|  | G01R 33/44 |
· · | using nuclear magnetic resonance (NMR) (Fulltext... Hierarchy... Expanded...G01R 33/24, Fulltext... Hierarchy... Expanded...G01R 33/62 take precedence) [5]

|  | G01R 33/46 |
· · · | NMR spectroscopy [5]

|  | G01R 33/465 |
· · · · | applied to biological material, e.g. in vitro testing [6]

|  | G01R 33/48 |
· · · | NMR imaging systems [5]

|  | G01R 33/483 |
· · · · | with selection of signal or spectra from particular regions of the volume, e.g. in vivo spectroscopy [6]

|  | G01R 33/485 |
· · · · · | based on chemical shift information [6]

|  | G01R 33/50 |
· · · · | based on the determination of relaxation times [5]

|  | G01R 33/54 |
· · · · | Signal processing systems, e.g. using pulse sequences [5]

|  | G01R 33/56 |
· · · · · | Image enhancement or correction, e.g. subtraction or averaging techniques [5]

|  | G01R 33/561 |
· · · · · · | by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences [6]

|  | G01R 33/563 |
· · · · · · | of moving material, e.g. flow-contrast angiography [6]

|  | G01R 33/565 |
· · · · · · | Correction of image distortions, e.g. due to magnetic field inhomogeneities [6]

|  | G01R 33/567 |
· · · · · · | gated by physiological signals [6]

|  | G01R 33/58 |
· · · · | Calibration of imaging systems, e.g. using test probes [5]

|  | G01R 33/60 |
· · | using electron paramagnetic resonance (Fulltext... Hierarchy... Expanded...G01R 33/24, Fulltext... Hierarchy... Expanded...G01R 33/62 take precedence) [5]

|  | G01R 33/62 |
· · | using double resonance (Fulltext... Hierarchy... Expanded...G01R 33/24 takes precedence) [5]

|  | G01R 33/64 |
· · | using cyclotron resonance (Fulltext... Hierarchy... Expanded...G01R 33/24 takes precedence) [5]

P:0 |  | G01R 35/00 |
Testing or calibrating of apparatus covered by the other groups of this subclass [2]

|  | G01R 35/02 |
· | of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating

|  | G01R 35/04 |
· | of instruments for measuring time integral of power or current

|  | G01R 35/06 |
· · | by stroboscopic methods