ASTM_F_2112_-_02_2011.pdf

Designation:F211202(Reapproved 2011)Standard Terminology forMembrane Switches1This standard is issued under the fixed designation F2112;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 terminology defines terms that are commonly usedin the membrane switch industry.1.2 These definitions are not mutually exclusive.2.Terminologyactuation forcethe maximum force measured prior to orincluding point at which contact closure is achieved on amembrane switch.bendto force from a straight form into different and espe-cially a curved one.bend cyclea fold of a sample around a specified mandrelwhich is“rolled”in one direction,followed by rolling in theopposite direction,returning the sample to its originalposition.circuit resistanceelectrical resistance as measured betweentwo test points whose internal contacts,when held closed,complete a circuit.conductor resistancethe measured electrical resistancethrough a circuit loop between two test points.contact bounceintermittent contact opening and contactclosure that may occur after switch operation.contact closurethe event at which a specified resistance isachieved on a membrane switch.contact forcethe force at contact closure.creasea ridge or groove made by folding and pressing.crease cyclea 180 degree crease followed by a flattening ofthe crease.current carrying capacitythe maximum level of electricalcurrent that a circuit can conduct without sustaining damage.dielectric withstand voltagethe maximum voltage a dielec-tric can withstand in a membrane switch without a visualchange from a voltage discharge or specified change ofinsulation resistance,or both.duty cyclethe ratio of switch closed time to total cycle time.graphic layeroptional decorated layer of a membraneswitch.See Fig.1.insulation resistancethe electrical resistance between twoisolated test points on a membrane switch.leakage currentcurrent flow through the insulation betweentest points.membrane layera flexible dynamic layer which carries oneor both switch poles the deflection of which is used to shortboth poles together.The membrane layer is a requiredcomponent of a membrane switch.See Fig.1.membrane switcha momentary switching device in whichat least one contact is on,or made of,a flexible substrate.membrane switch flex tailflexible portion of a membraneswitch used for input/output connection.nontactile switcha switch assembly that has a tactile ratioequal to zero.open circuit resistanceminimum allowable resistance asmeasured between two test points that,if lower than,willindicate an electrical short.power capacityelectrical power is defined as current voltage=V I(watts)rigid layerprovides mechanical support for the membraneswitch.See Fig.1.silver migrationa process by which silver,when in contactwith insulating materials under electrical potential,is re-moved ionically from its original location,and is redepositedas a metal(silver dendrite)at some other location.spacer layera material(usually dielectric)sometimes usedto maintain a separation between the membrane layer andstatic layer of a membrane switch.specified circuit resistancemaximum allowable circuit re-sistance as measured between two terminations whose inter-nal contacts,when held closed,complete a circuit.1This terminology is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved Feb.1,2011.Published March 2011.Originallyapproved in 2001.Last previous edition approved in 2002 as F2112-02.DOI:10.1520/F2112-02R11.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 static layera mechanically supported layer which carriesone or both poles of the switch or is used to short both polestogether.The static layer is a required component of amembrane switch.See Fig.1.tactile layeroptional feature incorporated into a membraneswitch to alter the tactile response.See Fig.1.tactile responsea physical sensation caused by a suddencollapse and/or snapback of a membrane switch.tactile switcha switch assembly that provides a tactile ratiogreater than zero.test pointstwo preselected conductive points in a circuitloop,possibly including a switch.travelmeasured distance of movement when a membraneswitch is depressed.ASTM 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