1ScopeThepurposeofthistestistomeasurethecapaci-
tanceeffectsarisingfromplasticsubstrates,adhesives,or
coatings,whichmaybecriticaltothereliablefunctioningofa
circuit.
2ApplicableDocumentsNone
3TestSpecimenSpecimenthicknessforalltestsmustbe
uniformwithin±1%oftheaveragethickness.Atfrequencies
below1MHzthespecimenshallbelargeenoughtoprovide
circularelectrodesatleast10cmindiameterandbetween
1.5mmto6.35mmthick.Atfrequenciesfrom1.0MHzto
1000MHz,amicrometerelectrodeholdershouldbeused
withthetestspecimen.
4Equipment/Apparatus
4.1Abridgeorresonantcircuitcapableofmeasuringthe
capacitanceanddissipationfactorwiththerequiredaccuracy
atthespecifiedfrequencymaybeused.Theinherentaccu-
racyofthemeasurementshallbe±0.5%,±0.2%picofarad,
unlessotherwisespecified.Theelectrodematerialmaybethin
foil,evaporatedmetal,sprayedmetal,orairdryingconductive
paint.
4.2Thegeneratingcircuitmaybeanysuitablesourcethat
canfurnishsufficientcurrentforthespecifiedprecisionof
measurementorvoltagegradientinthedielectric.
5Procedure
5.1PreparationTheatmosphericconditionssurrounding
thespecimenpriortoandduringtestmustbe23°C,±1.1°C
and50%,±4%RH.
5.2TestPlacethetestspecimeninasuitablemeasuring
cellorholderandmeasureitscapacitanceanddissipation
factorwithasuitablemeasuringcircuithavingrequiredsensi-
tivityandaccuracy.
5.3EvaluationRecordtheshapeanddimensionsofthe
specimen,typeanddimensionsofelectrodesandmeasuring
cell,testconditions,methodofmeasurement,appliedvoltage,
voltagegradient,andfrequencyandcapacitance.
5.4Calculation
C=
Q
V
=
GA
4pido
=
A
4pido
where:
C=capacitanceinFarads
Q=totalchargeincoulombs
V=potentialdifferencebetweenplatesinvolts
GA=areaofplates
4pido=distancebetweenplates
6Notes
6.1Suitablemeasurementtechniquesmustbeusedtomini-
mizeerrorsduetotheconnectionsbetweenthemeasuring
apparatusandthespecimen.
6.2TheACvoltageactuallyimpressedacrossthespecimen
mustbeaslowaspossible.WhenDCpolarizingvoltagesare
required,itmustbeasspecified.
TheInstituteforInterconnectingandPackagingElectronicCircuits
2215SandersRoad?Northbrook,IL60062
IPC-TM-650
TESTMETHODSMANUAL
Number
2.5.2
Subject
CapacitanceofInsultingMaterials
Date
7/75
Revision
A
OriginatingTaskGroup
N/A
MaterialinthisTestMethodsManualwasvoluntarilyestablishedbyTechnicalCommitteesoftheIPC.Thismaterialisadvisoryonly
anditsuseoradaptationisentirelyvoluntary.IPCdisclaimsallliabilityofanykindastotheuse,application,oradaptationofthis
material.Usersarealsowhollyresponsibleforprotectingthemselvesagainstallclaimsorliabilitiesforpatentinfringement.
EquipmentreferencedisfortheconvenienceoftheuseranddoesnotimplyendorsementbytheIPC.
Page1of1
|
|
