1、Designation: F 1762 07Standard Practice forExposing a Membrane Switch to Variation in AtmosphericPressure1This standard is issued under the fixed designation F 1762; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure for exposing a mem-brane switch to variations in atmospheric pressure. It can beused to d
3、etermine the effects of pressure variations on chemicaland mechanical properties and functional characteristics of theswitch.2. Terminology2.1 Definitions:2.1.1 circuit resistanceelectrical resistance as measuredbetween two test points whose internal contacts, when heldclosed, complete a circuit.2.1
4、.2 contact closurethe event at which a specified resis-tance is achieved on a membrane switch.2.1.3 membrane switcha momentary switching device inwhich at least one contact is on, or made of, a flexiblesubstrate.2.1.4 specified resistancethe maximum allowable circuitresistance as measured between tw
5、o test points whose internalcontacts, when held closed, complete a circuit.2.1.5 test pointstwo preselected conductive points in acircuit loop, possibly including a switch.3. Significance and Use3.1 Erratic operation or malfunction of a membrane switchresulting from changes in the specified switch c
6、haracteristics,3.2 Rupture, implosion or explosion of seals due to pressurevariations,3.3 Change in physical or chemical properties due to pres-sure differentiations, and3.4 Delaminations of a membrane switch may occur due topressure variations.4. Interferences4.1 Time duration before, during and af
7、ter pressure cycling,4.2 Temperature,4.3 Humidity,4.4 Mounting Method (if applicable).5. Apparatus5.1 Pressure Chamber, a chamber or cabinet capable ofmaintaining a specified pressure. If procedurally required, theapparatus shall be capable of providing pressure variation at aspecified rate.5.2 Moni
8、toring Device, suitable to detect contact closure(that is, ohm meter, etc.).6. Conditioning6.1 Condition all specimens for 72 h at ambient laboratoryconditions immediately prior to exposure, or prior to pressurecycling. This is to enable the specimens to stabilize.7. Procedure7.1 Pretest Setup:7.1.1
9、 Measure or observe the desired characteristics of theswitch so that comparable measurements and observations canbe made during or after the test.7.1.1.1 Document the setup, test equipment, and mountingprocedure (if applicable) used to measure the characteristics.7.1.2 Connect predetermined switch t
10、erminations to contactclosure measuring device.7.2 In-Process Test:7.2.1 Place specimens in the chamber at ambient conditions,record time and date, and initiate contact closure monitoringdevice.7.2.2 Adjust the ramp rate to decrease air pressure at 2000ft/min unless otherwise specified.7.2.3 Set pre
11、ssure as specified.7.2.4 Maintain the chamber pressure for the specified timeinterval.7.2.5 Return chamber pressure to the initial ambient condi-tions at the specified rate.7.2.6 Remove specimens and record time and date.7.3 Post Test:7.3.1 Measure and observe the characteristics of the switchas in
12、7.1.1. Record time and date for each characteristicmeasured.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved Dec. 1, 2007. Published December 2007. Originallyapproved i
13、n 1996. Last previous edition approved in 2002 as F 176202.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8. Precision and Bias8.1 The precision and bias of this test are under investiga-tion.9. Keywords9.1 contact closure; delamina
14、tion; membrane switchASTM 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 infringemen
15、t 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 f
16、or 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 know
17、n to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, 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 1762 072
