ASTM F1681-07a
(Test Method)Standard Test Method for Determining Current Carrying Capacity of a Conductor as Part of a Membrane Switch Circuit
Standard Test Method for Determining Current Carrying Capacity of a Conductor as Part of a Membrane Switch Circuit
SIGNIFICANCE AND USE
p>Current carrying capacity is used by designers and manufacturers of electronic interface circuitry to ensure that the membrane switch can reliably handle the loads occurring in normal use and under extreme circumstances. A thorough understanding of CCC allows manufacturers to take it into account when developing design rules for membrane switches.
Failures due to exceeding the CCC of a circuit may take the form of a significant change in conductor resistance, insulation breakdown (shorts), or conductor breakdown (opens).
Since a number of design parameters, such as trace width, ink film thickness, etc. affect the final test results, any conclusions should only be applied to specific designs, rather than to a general combination of materials.
Current carrying capacity tests may be destructive and units that have been tested should be considered unreliable for future use.
Current carrying capacity may be significantly different for static loads and dynamic (that is, cycling) loads. Failure modes are also generally different.
The use of a thermocouple to monitor the temperature of the UUT may be helpful to monitor the progress of the test.
Initial expected starting current should be calculated in advance to prevent damage to test equipment.
SCOPE
1.1 This test method covers the determination of the current carrying capacity of a conductor as part of a membrane switch.
1.2 This test method may be used to test a circuit to destruction, that is, to determine its maximum current carrying capacity, or it may be used to test the ability of a circuit to withstand a desired current level.
1.3 This test method applies only to static conditions, and does not apply to contact closure cycling of a membrane switch under current load (test method forthcoming).
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: F1681 − 07a
StandardTest Method for
Determining Current Carrying Capacity of a Conductor as
1
Part of a Membrane Switch Circuit
This standard is issued under the fixed designation F1681; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.4 membrane switch—a momentary switching device in
which at least one contact is on, or made of, a flexible
1.1 This test method covers the determination of the current
substrate.
carrying capacity of a conductor as part of a membrane switch.
3.1.5 power capacity—electrical power is defined as cur-
1.2 This test method may be used to test a circuit to
rent×voltage=V×I (watts).
destruction, that is, to determine its maximum current carrying
3.1.6 test points—two preselected conductive points in a
capacity, or it may be used to test the ability of a circuit to
circuit loop, possibly including a switch.
withstand a desired current level.
1.3 This test method applies only to static conditions, and
4. Significance and Use
doesnotapplytocontactclosurecyclingofamembraneswitch
4.1 Current carrying capacity is used by designers and
under current load (test method forthcoming).
manufacturers of electronic interface circuitry to ensure that
1.4 This standard does not purport to address all of the
themembraneswitchcanreliablyhandletheloadsoccurringin
safety concerns, if any, associated with its use. It is the
normal use and under extreme circumstances. A thorough
responsibility of the user of this standard to establish appro-
understanding of CCC allows manufacturers to take it into
priate safety and health practices and determine the applica-
account when developing design rules for membrane switches.
bility of regulatory limitations prior to use.
4.2 Failures due to exceeding the CCC of a circuit may take
2. Referenced Documents
the form of a significant change in conductor resistance,
2
insulation breakdown (shorts), or conductor breakdown
2.1 ASTM Standards:
(opens).
F1578Test Method for Contact Closure Cycling of a Mem-
brane Switch
4.3 Since a number of design parameters, such as trace
F1680Test Method for Determining Circuit Resistance of a
width, ink film thickness, etc. affect the final test results, any
Membrane Switch
conclusions should only be applied to specific designs, rather
than to a general combination of materials.
3. Terminology
4.4 Current carrying capacity tests may be destructive and
3.1 Definitions:
units that have been tested should be considered unreliable for
3.1.1 conductor resistance—the measured electrical resis-
future use.
tance through a circuit loop between two test points.
4.5 Current carrying capacity may be significantly different
3.1.2 Discussion—When a switch is included in that loop, it
for static loads and dynamic (that is, cycling) loads. Failure
shall be ``closed” in accordance with Test Method F1680.
modes are also generally different.
3.1.3 current carrying capacity (CCC)—themaximumlevel
4.6 Theuseofathermocoupletomonitorthetemperatureof
of electrical current that a circuit can conduct without sustain-
the UUT may be helpful to monitor the progress of the test.
ing damage.
4.7 Initial expected starting current should be calculated in
1
advance to prevent damage to test equipment.
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
Switches.
5. Interferences
Current edition approved Dec. 1, 2007. Published December 2007. Originally
5.1 The following parameters may affect the results of this
approved in 1996. Last previous edition approved in 2007 as F1681–07. DOI:
10.1520/F1681-07A.
test:
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1.1 Temperature,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1.2 Relative humidity, and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 5.1.3 Barometric pressure.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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---------------------- Page: 1 ----------------------
F1681 − 07a
6. Hazard repeated using a higher power (voltage and current) level, a
change in the voltage range is permissible.
6.1 The user must be aware of the operating range of their
8.2.5 At the conclusion of testing record the final results as
equipment to prevent damage to the device from overload
in 8.2.2.
during testing. For example, the current should be adjusted
startingfromaminimumsetting,andadecadeboxshouldstart
9. Calculations
on the highest r
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:F 1681–07 Designation:F 1681–07a
Standard Test Method for
Determining Current Carrying Capacity of a Conductor as
1
Part of a Membrane Switch Circuit
This standard is issued under the fixed designation F 1681; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of the current carrying capacity of a conductor as part of a membrane switch.
1.2 This test method may be used to test a circuit to destruction, that is, to determine its maximum current carrying capacity,
or it may be used to test the ability of a circuit to withstand a desired current level.
1.3 This test method applies only to static conditions, and does not apply to contact closure cycling of a membrane switch under
current load (test method forthcoming).
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
F 1578 Test Method for Contact Closure Cycling of a Membrane Switch
F 1680 Test Method for Determining Circuit Resistance of a Membrane Switch
3. Terminology
3.1 Definitions:
3.1.1 conductor resistance—the measured electrical resistance through a circuit loop between two test points.
3.1.2 Discussion—When a switch is included in that loop, it shall be 88closed” in accordance with Test Method F 1680.
3.1.3 current carrying capacity (CCC)—the maximum level of electrical current that a circuit can conduct without sustaining
damage.
3.1.4 membrane switch—a momentary switching device in which at least one contact is on, or made of, a flexible substrate.
3.1.5 power capacity—electrical power is defined as current 3 voltage = V 3 I (watts).
3.1.6 test points—two preselected conductive points in a circuit loop, possibly including a switch.
4. Significance and Use
4.1 Current carrying capacity is used by designers and manufacturers of electronic interface circuitry to ensure that the
membrane switch can reliably handle the loads occurring in normal use and under extreme circumstances. A thorough
understanding of CCC allows manufacturers to take it into account when developing design rules for membrane switches.
4.2 Failures due to exceeding the CCC of a circuit may take the form of a significant change in conductor resistance, insulation
breakdown (shorts), or conductor breakdown (opens).
4.3 Since a number of design parameters, such as trace width, ink film thickness, etc. affect the final test results, any conclusions
should only be applied to specific designs, rather than to a general combination of materials.
4.4 Current carrying capacity tests may be destructive and units that have been tested should be considered unreliable for future
use.
4.5 Current carrying capacity may be significantly different for static loads and dynamic (that is, cycling) loads. Failure modes
are also generally different.
4.6 The use of a thermocouple to monitor the temperature of the UUT may be helpful to monitor the progress of the test.
4.7 Initial expected starting current should be calculated in advance to prevent damage to test equipment.
1
This test method is under the jurisdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane Switches .
Current edition approved JulyDec. 1, 2007. Published AugustDecember 2007. Originally approved in 1996. Last previous edition approved in 20022007 as
F1681–96(2002).F 1681–07.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
F 1681–07a
5. Interferences
5.1 The following parameters may affect the results of this test:
5.1.1 Temperature,
5.1.2 Relative humidity, and
5.1.3 Barometric pressure.
6. Hazard
6.1 The user must be aware of the operating range of their equipment to prevent damage to the device fr
...
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