ASTM_F_1663_-_15.pdf

Designation:F166315Standard Test Method forDetermining the Capacitance of a Membrane Switch orPrinted Electronic Device1This standard is issued under the fixed designation F1663;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of capaci-tance(s)of a membrane switch or printed electronic device.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions:2.1.1 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.2.1.2 test pointstwo preselected mutually insulated loca-tions on switch assembly.3.Significance and Use3.1 Capacitance testing is useful for design verification,quality control of materials,and workmanship.3.2 High capacitance may interfere with the reliable perfor-mance of interface electronics.3.3 Specific areas of testing are,but not limited to:3.3.1 Conductor/dielectric/conductor crossing point,3.3.2 Close proximity of conductors,and3.3.3 Any other conductive surface such as shielding ormetal backing panel.4.Interferences4.1 The following parameters may affect the results of thistest:4.1.1 Humidity,4.1.2 Contamination,4.1.3 Barometric pressure,and4.1.4 Temperature.5.Apparatus5.1 Electronic Test Instrument,for measuring very smallcapacitance(pico-farad range).6.Procedure6.1 Pretest Setup:6.1.1 Suspend the switch specimen in air or otherwiseisolate it from any interfering affects.6.1.2 Attach to the capacitance measuring instrument anynecessary leads,probes or connectors required to connect themembrane switch assembly or printed electronic device formeasurement.Place test leads as close to test points as possiblewithout physical connection.(This will reduce any variationsdue to lead positioning).6.1.3 Record the capacitance reading indicated on the in-strument to equal capacitance(Ci)(this is the capacitance ofthe test setup).6.2 In-Process Test:6.2.1 Connect test leads to the test points.6.2.2 Record the capacitance reading indicated on the in-strument to equal total capacitance(Ct)(this is the totalcapacitance of the switch and device.7.Calculation7.1 Calculate the capacitance of the switch specimen asfollows:CapacitanceCs!5 Ct2 Ci8.Report8.1 Report the following information:8.1.1 Temperature,8.1.2 Humidity,8.1.3 Barometric pressure,8.1.4 Date of test,8.1.5 Part number or description of the switch specimen,orboth,8.1.6 Conductive path(s)tested and the connection pointsused.8.1.7 Capacitance,(Ci),8.1.8 Total capacitance,(Ct),1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on PrintedElectronics.Current edition approved June 1,2015.Published July 2015.Originally approvedin 1995.Last previous edition approved in 2009 as F1663-09.DOI:10.1520/F1663-15.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.1.9 Capacitance of the switch specimen,(Cs),8.1.10 Detailed description of isolation setup used,(includ-ing lead length,connection type,and sensitivity range),and8.1.11 Detailed description of test equipment.9.Precision and Bias9.1 PrecisionIt is not possible to specify the precision ofthe procedure in Test Method F1663 for measuring capacitancebecause inter-laboratory studies have proven inconclusive dueto insufficient participating laboratories with the appropriateequipment.9.2 BiasNo information can be presented on the bias ofthe procedure in Test Method F1663 for measuring capacitancebecause no standard sample is available for this industry.10.Keywords10.1 capacitance;membrane switch or printed electronicdeviceASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you shouldmake your views k