1、Designation: F 1663 09Standard Test Method forDetermining the Capacitance of a Membrane Switch1This standard is issued under the fixed designation F 1663; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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.1.2 This standard does not purport to address all of
3、 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 swit
4、ching 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 c
5、apacitance 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 pane
6、l.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
7、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 for measurement. Place test leadsas close to test points as possible wi
8、thout physical connection.(This will reduce any variations due 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
9、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:Capacitance Cs! 5 Ct2 Ci8. Report8.1 Report the following information:8.1.1 Temperature
10、,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),8.1.9 Capacitance of the switch specimen, (Cs),1This test m
11、ethod is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved June 15, 2009. Published July 2009. Originallyapproved in 1995. Last previous edition approved in 2002 as F 1663-95(2002).1Copyrigh
12、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 P
13、recisionIt is not possible to specify the precision ofthe procedure in Test Method F 1663 for measuring capaci-tance because inter-laboratory studies have proven inconclu-sive due to insufficient participating laboratories with theappropriate equipment.9.2 BiasNo information can be presented on the
14、bias ofthe procedure in Test Method F 1663 for measuring capaci-tance because no standard sample is available for this industry.10. Keywords10.1 capacitance; membrane switchASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentione
15、din 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
16、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
17、theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C
18、700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 1663 092
