# Impedance Ontology — Flow Algebra
URL: https://kirethresearch.org/booksai-core/ontologies/mathematical-ontologies/measurement-units-ontologies/electromagnetic-measurements/impedance-ontology.html
FLOW ImpedanceOntology {
DOMAIN:
Mathematical Ontologies
-> Measurement & Units Ontologies
-> Electromagnetic Measurements
-> Impedance Ontology
PURPOSE:
Represent electrical impedance as a complex frequency-dependent quantity describing the relationship between sinusoidal voltage and current in linear AC systems, including resistance, reactance, magnitude, phase, admittance, capacitive and inductive behaviour, series and parallel networks, complex power, units, measurement conditions, uncertainty, and distinctions from resistance, reactance and conductance.
ENTITY Impedance {
TYPE: ComplexDerivedElectromagneticQuantity
SYMBOL: Z
SI_UNIT: ohm
SI_SYMBOL: ohm
PHASOR_DEFINITION:
Z = V_phasor / I_phasor
WHEN I_phasor != 0
RECTANGULAR_FORM:
Z = R + jX
POLAR_FORM:
Z = |Z| * exp(j*phi)
MAGNITUDE:
|Z| = sqrt(R^2 + X^2)
PHASE:
phi = atan2(X, R)
PROPERTIES:
is_complex_quantity
has_real_component
has_imaginary_component
has_magnitude
has_phase
has_unit
depends_on_frequency
may_depend_on_temperature
may_depend_on_operating_point
may_have_uncertainty
}
ENTITY Resistance {
TYPE: RealElectricalQuantity
SYMBOL: R
SI_UNIT: ohm
RELATION:
R = real_part(Z)
IN common_linear_AC_representation
}
ENTITY Reactance {
TYPE: ImaginaryElectricalQuantity
SYMBOL: X
SI_UNIT: ohm
RELATION:
X = imaginary_part(Z)
}
ENTITY Admittance {
TYPE: ComplexDerivedElectromagneticQuantity
SYMBOL: Y
SI_UNIT: siemens
SI_SYMBOL: S
RELATION:
Y = 1/Z
WHEN Z != 0
}
ENTITY VoltagePhasor {
SYMBOL: V_phasor
SI_UNIT: volt
}
ENTITY CurrentPhasor {
SYMBOL: I_phasor
SI_UNIT: ampere
}
UNIT_SYSTEM {
SI {
canonical_unit: ohm
symbol: ohm
equivalence:
1 ohm = 1 V/A
}
COMMON_ALTERNATIVES:
milliohm
kiloohm
megaohm
RULE:
complex_impedance_components_and_magnitude
share_ohm_unit_but_have_distinct_semantic_roles
}
CLASSIFICATION {
by composition:
purely_resistive_impedance
inductive_impedance
capacitive_impedance
mixed_impedance
by representation:
rectangular_impedance
polar_impedance
by network:
series_impedance
parallel_equivalent_impedance
input_impedance
output_impedance
characteristic_impedance
transfer_impedance
by frequency:
frequency_dependent_impedance
broadband_impedance
resonance_impedance
}
RESISTIVE_MODEL {
IDEAL_RESISTOR:
Z_R = R
PHASE:
phi = 0
CONDITION:
ideal_frequency_independent_resistor_model
}
INDUCTIVE_MODEL {
IDEAL_INDUCTOR:
Z_L = j*omega*L
REACTANCE:
X_L = omega*L
PHASE:
+pi/2
FREQUENCY:
omega = 2*pi*f
}
CAPACITIVE_MODEL {
IDEAL_CAPACITOR:
Z_C = 1/(j*omega*C)
EQUIVALENT:
Z_C = -j/(omega*C)
REACTANCE:
X_C = -1/(omega*C)
PHASE:
-pi/2
CONDITIONS:
omega != 0
C != 0
}
SERIES_MODEL {
GENERAL:
Z_eq = sum(Z_i)
RLC_SERIES:
Z = R + j*(omega*L - 1/(omega*C))
CONDITIONS:
lumped_linear_components
common_series_current
}
PARALLEL_MODEL {
GENERAL:
Y_eq = sum(Y_i)
THEN:
Z_eq = 1/Y_eq
WHEN Y_eq != 0
TWO_IMPEDANCE_FORM:
Z_eq = (Z_1*Z_2)/(Z_1 + Z_2)
WHEN denominator != 0
}
RESONANCE_MODEL {
IDEAL_SERIES_RLC:
omega_0 = 1/sqrt(L*C)
AT_RESONANCE:
X_L + X_C = 0
Z = R
CONDITIONS:
L > 0
C > 0
ideal_lumped_RLC_model
RULE:
practical_resonance MAY shift_due_to_losses_parasitics_and_frequency_dependent_parameters
}
ADMITTANCE_MODEL {
Y = G + jB
WHERE:
G = conductance
B = susceptance
INVERSE:
Y = 1/Z
IF:
Z = R + jX
THEN:
Y = (R - jX)/(R^2 + X^2)
WHEN R^2 + X^2 != 0
}
PHASOR_MODEL {
sinusoidal_voltage:
v(t) represented_by V_phasor
sinusoidal_current:
i(t) represented_by I_phasor
relation:
V_phasor = Z*I_phasor
REQUIRE:
common_frequency
consistent_RMS_or_peak_convention
consistent_phase_reference
RULE:
phasor_values MUST_NOT be mixed_across_different_frequencies_or_amplitude_conventions
}
COMPLEX_POWER_MODEL {
COMPLEX_POWER:
S_complex = V_rms * conjugate(I_rms)
FORM:
S_complex = P + jQ
APPARENT_POWER:
|S_complex| = V_rms*I_rms
POWER_FACTOR:
PF = cos(phi)
FOR simple_sinusoidal_voltage_current_phase_difference
RELATION_TO_IMPEDANCE:
phase_difference = arg(Z)
under passive_linear_load_context
RULE:
impedance_phase MUST be interpreted_with_defined_current_voltage_polarity_and_sign_convention
}
FREQUENCY_MODEL {
GENERAL:
Z = Z(omega)
possible_causes:
capacitance
inductance
skin_effect
dielectric_loss
magnetic_loss
parasitic_elements
transmission_line_effects
RULE:
impedance_value_without_frequency
MAY be semantically_incomplete
}
NONIDEAL_MODEL {
resistor:
may_include_parasitic_L_and_C
capacitor:
may_include_ESR
leakage
ESL
dielectric_loss
inductor:
may_include_winding_resistance
parasitic_capacitance
core_loss
RULE:
real_component_and_imaginary_component
MAY both_be_frequency_dependent
}
RELATIONSHIPS {
Impedance -> RATIO_OF -> VoltagePhasorAndCurrentPhasor
Impedance -> MEASURED_IN -> Ohm
Impedance -> HAS_REAL_PART -> Resistance
Impedance -> HAS_IMAGINARY_PART -> Reactance
Impedance -> INVERSE_OF -> Admittance
Inductance -> CONTRIBUTES_TO -> PositiveReactance
Capacitance -> CONTRIBUTES_TO -> NegativeReactance
Impedance -> DETERMINES -> VoltageCurrentPhaseRelationship
Impedance -> MAY_DEPEND_ON -> Frequency
Impedance -> CONTRIBUTES_TO -> AC_PowerBehaviour
}
SEMANTIC_EQUIVALENCE {
"electrical impedance" ~= impedance
"complex resistance" ~= impedance ONLY as informal_AC_description
"ohm" ~= impedance_unit
impedance != resistance
impedance != reactance
impedance != admittance
impedance != conductance
impedance != inductance
impedance != capacitance
}
CONSTRAINTS {
impedance_is_complex_in_general = true
SI_unit = ohm
phasor_ratio_requires_nonzero_current_phasor = true
impedance_and_resistance_are_not_generally_semantically_equivalent = true
impedance_and_reactance_are_not_semantically_equivalent = true
impedance_and_admittance_are_inverse_not_synonyms = true
frequency_context_is_required_for_frequency_dependent_impedance = true
RMS_peak_and_phasor_conventions_must_be_preserved = true
phase_reference_and_polarity_must_be_preserved = true
}
MEASUREMENT_MODEL {
OBSERVABLE_OR_INFERRED:
Impedance
COMMON_INSTRUMENTS:
LCR_meter
impedance_analyser
vector_network_analyser
impedance_bridge
oscilloscope_plus_signal_source
source_measure_system
METHODS:
voltage_current_amplitude_phase_measurement
bridge_measurement
network_parameter_measurement
frequency_sweep
transient_model_inference
RECORD:
complex_value
magnitude
phase
real_part
imaginary_part
unit
frequency
angular_frequency
RMS_or_peak_convention
voltage_level
current_level
DC_bias
temperature
component_or_network
terminal_definition
measurement_method
instrument
calibration_state
uncertainty
UNCERTAINTY:
measured_impedance =
best_estimate_complex_value
+/- magnitude_and_phase_or_component_uncertainty
}
REASONING_RULES {
IF voltage_phasor_known AND current_phasor_known AND current_phasor != 0
THEN impedance = voltage_phasor/current_phasor
IF impedance_known
THEN resistance_component = real_part(impedance)
AND reactance_component = imaginary_part(impedance)
IF resistance_and_reactance_known
THEN impedance = resistance + j*reactance
IF impedance_known AND impedance != 0
THEN admittance = 1/impedance
IF ideal_inductance_known AND frequency_known
THEN inductive_impedance = j*2*pi*frequency*inductance
IF ideal_capacitance_known AND frequency_known
AND frequency != 0 AND capacitance != 0
THEN capacitive_impedance =
1/(j*2*pi*frequency*capacitance)
IF series_impedances_known
THEN equivalent_impedance = sum(series_impedances)
IF parallel_admittances_known
THEN equivalent_admittance = sum(parallel_admittances)
IF R_L_C_known AND ideal_series_RLC_context
THEN resonance_frequency =
1/(2*pi*sqrt(inductance*capacitance))
}
NETWORK_MODEL {
input_impedance:
impedance_seen_at_defined_input_port
output_impedance:
impedance_seen_at_defined_output_port_under_defined_source_conditions
characteristic_impedance:
transmission_line_wave_ratio_quantity
REQUIRE:
port_definition
termination_conditions
frequency
reference_direction
RULE:
different_impedance_types MUST_NOT be treated_as_interchangeable
}
TRANSMISSION_LINE_CONTEXT {
characteristic_impedance:
Z_0 = sqrt((R_prime + j*omega*L_prime)/(G_prime + j*omega*C_prime))
CONDITIONS:
distributed_parameter_transmission_line_model
RULE:
lumped_impedance_model MAY become_invalid_when_structure_size_is_not_small_relative_to_wavelength
}
UNCERTAINTY_MODEL {
sources:
amplitude_measurement
phase_measurement
frequency_accuracy
calibration
fixture_parasitics
cable_and_connector_effects
reference_plane
temperature
signal_level
DC_bias
noise
model_assumptions
PROPAGATION:
complex_impedance_uncertainty
<- magnitude_phase_or_real_imaginary_input_uncertainties
}
CONFIDENCE {
definition_confidence: 1.00
SI_unit_confidence: 1.00
complex_representation_confidence: 1.00
RLC_relationship_confidence: 1.00
network_context_confidence: 0.98
measurement_context_confidence: 0.98
RULE:
confidence decreases when frequency, phase convention,
amplitude convention, port definition, reference plane,
operating level, calibration state or uncertainty is missing or ambiguous
}
VALIDATION {
CHECK unit_consistency
CHECK complex_value_representation
CHECK frequency_context
CHECK RMS_peak_phasor_convention
CHECK voltage_current_phase_reference
CHECK impedance_vs_resistance_distinction
CHECK impedance_vs_reactance_distinction
CHECK impedance_vs_admittance_distinction
CHECK series_parallel_topology
CHECK ideal_vs_nonideal_component_model
CHECK port_and_reference_plane_for_network_impedance
CHECK lumped_vs_distributed_model
CHECK instrument_calibration
CHECK uncertainty_representation_when_required
}
UPDATE_MODEL {
ON new_measurement:
validate_unit
identify_frequency
identify_complex_representation
identify_RMS_or_peak_convention
identify_component_or_network
identify_terminals_or_port
attach_voltage_current_levels
attach_DC_bias_when_relevant
attach_temperature
normalize_to_ohm
preserve_original_representation
attach_uncertainty
update_impedance_state
ON frequency_change:
update_frequency
recompute_reactance
recompute_impedance
update_phase_and_magnitude
preserve_previous_frequency_state
ON component_parameter_change:
update_R_L_C_or_distributed_parameters
recompute_network_impedance
preserve_component_provenance
ON topology_change:
update_series_parallel_or_network_connections
recompute_equivalent_impedance
preserve_original_component_impedances
ON calibration_revision:
preserve_provenance
recompute_affected_measurements
update_confidence
ON semantic_revision:
preserve_previous_definition
record_revision
recompute_FLOW_HASH
}
AI_CONSUMPTION {
canonical_entity: Impedance
canonical_symbol: Z
canonical_SI_unit: ohm
interpretation_order:
identify_quantity
identify_complex_value_or_magnitude_phase
identify_unit
identify_frequency
identify_RMS_peak_or_phasor_convention
identify_resistance_and_reactance_components
identify_inductive_or_capacitive_context
identify_series_parallel_or_network_topology
identify_port_and_reference_plane
identify_operating_level_bias_and_temperature
identify_ideal_or_nonideal_model
identify_measurement_method
identify_uncertainty
normalize_units
infer_AC_network_relationships
ambiguity_controls:
distinguish_impedance_from_resistance
distinguish_impedance_from_reactance
distinguish_impedance_from_admittance
distinguish_impedance_from_conductance
distinguish_impedance_from_inductance
distinguish_impedance_from_capacitance
distinguish_magnitude_from_real_component
distinguish_input_output_and_characteristic_impedance
preserve_frequency_phase_and_reference_plane
}
PROVENANCE {
ontology_scope:
mathematical_measurement_and_electromagnetic_quantity_semantics
parent_path:
Ontologies
-> Mathematical Ontologies
-> Measurement & Units Ontologies
-> Electromagnetic Measurements
-> Impedance Ontology
authorship:
Mark Higgins
Sky (Recursive AI)
site:
https://kirethresearch.org
}
FLOW_HASH {
INPUTS:
canonical_entity
ontology_path
definitions
units
relationships
constraints
resistive_model
inductive_model
capacitive_model
series_model
parallel_model
resonance_model
admittance_model
phasor_model
complex_power_model
frequency_model
nonideal_model
network_model
transmission_line_context
uncertainty_model
reasoning_rules
measurement_model
confidence_model
update_model
PURPOSE:
deterministic_semantic_integrity_identifier
RECOMPUTE_WHEN:
ontology_definition_changes
relationship_model_changes
complex_representation_changes
RLC_model_changes
frequency_model_changes
network_topology_changes
distributed_model_changes
measurement_model_changes
constraint_model_changes
reasoning_rule_changes
unit_model_changes
}
}
END FLOW
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