ASTM F1661-96

Standard Test Method for Determining the Contact Bounce Time of a Membrane Switch

SCOPE
1.1 This test method covers the determination of the contact bounce time of a membrane switch.  
1.2 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.

General Information

• Status: Historical
• Publication Date: 09-Dec-1996
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.18 - Printed Electronics

Relations

• Replaced By: ASTM F1661-96(2002) - Standard Test Method for Determining the Contact Bounce Time of a Membrane Switch
• Effective Date: 10-Dec-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1661 – 96
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Determining the Contact Bounce Time of a Membrane
1
Switch
This standard is issued under the fixed designation F 1661; 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 contact
bounce time of a membrane switch.
1.2 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 appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D 2240 Test Method for Rubber Property—Durometer
FIG. 1 Contact Bounce on Switch Break
2
Hardness
3. Terminology
tance measured between two terminations whose internal
switch contacts, when held closed, complete a circuit.
3.1 Definitions:
3.1.9 specified upper transition voltage, SUTV—minimum
3.1.1 contact bounce—intermittent contact opening and
allowable UTV.
contact closure that may occur after switch operation.
3.1.10 upper transition voltage, UTV—the voltage at which
3.1.2 contact bounce time (break), T —the time period
CBB
the switched logic device transitions to an 88on” state.
measured from the first instant V is equal to the SLTV until
M
3.1.11 voltage, measured, V —voltage measured across
the first instant it again falls below the SLTV after the last M
load Resistor (R ) by the oscilloscope and measured on it’s
instant it rises above the SUTV. If V does not rise above L
M
screen or voltage measured across the switch under test when
SUTV during the time interval, T = 0, (see Fig. 1).
CBB
a contact bounce measuring device is used.
3.1.3 contact bounce time (make), T —the time period
CBM
measured from the first instant V is equal to the SUTV until
M
4. Significance and Use
the first instant it again rises above the SUTV after the last
4.1 Contact bounce time is essential to manufacturers and
instant it falls below the SLTV. If V does not fall below SLTV
M
users when designing interface circuitry because it specifies the
during the time interval, T = 0, (see Fig. 2).
CBM
time delay necessary in the decoder circuitry to avoid any false
3.1.4 lower transition voltage, LTV—the voltage at which
signals caused by contact bounce. Allowing for time delay
the switched logic device transitions to an “off” state.
makes the switch operation considerably more reliable.
3.1.5 membrane switch—a momentary switching device in
which at least one contact is on, or made of, a flexible
substrate.
3.1.6 resistor, load, R —load resistance in series with
L
switch under test.
3.1.7 specified lower transition voltage, SLTV—minimum
allowable LTV.
3.1.8 specified resistance, R —maximum allowable resis-
S
1
This test method is under the jurisdiction of ASTM Committee F-1 on
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
Switches.
Current edition approved Dec. 10, 1996. Published February 1997. Originally
published as F 1661 – 95. Last previous edition F 1661 – 95.
2
Annual Book of ASTM Standards, Vol 09.01. FIG. 2 Contact Bounce on Switch Make
1

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F 1661
5. Interference
5.1 The following parameters may affect the results of this
test:
5.1.1 If a human finger is used in place of a mechanical
probe the results are more varied and larger sample sizes
should be used, and
5.1.2 Mechanical probe materials (hardness) and speed will
affect results.
6. Apparatus
6.1 Test Probe, built to either of the configuration shown in
Fig. 3 and Fig. 4 are acceptable but must be made of an inert
FIG. 4 Test Probe Option
elastomeric material with a hardness number equivalent to
A/45 6 5 as measured in accordance with Test Method
D 2240. Test probes that do not meet the above criteria must be
fully specified and recorded.
6.2 Test Surface—flat, smooth, unyielding, and larger than
switch under test.
6.3 Oscilloscope, with recording capabilities and power
supply, or suitable contact bounce time measuring instrument.
6.4 Device, which will consistently move probe into and FIG. 5 Test Setup Option
away from the switch at a controlled speed. Also capable of
applying a specified force.
8.1.1 Secure switch on test surface.
CONTACT BOUNCE TIME MEASURING
8.1.2 Connect switch terminals as shown in Fig. 6 so that:
INSTRUMENT METHOD
R 5 10 to 100 times R (1)
L S
7. Procedure
8.1.3 Adj
...