《ECA-448-1B-1993.pdf》由会员分享，可在线阅读，更多相关《ECA-448-1B-1993.pdf（7页珍藏版）》请在三一文库上搜索。
1、t EIA 448-LB 93 W 3234600 0505466 061 w Reproduced y GLOBAL ENGINEERING DOCUMENTS W Thr Pmnissbn d EIA ihdw Rgalty Apemcn ANSI/ EIA-448-18-1992 APPROVED: June 10, 1992 EIA STANDARD Method 15 Standard Test Method for Electromechanical Switches (Test for Contact Bounce) EU-448-1B (Revision B of Addend
2、um No. 1 t o EIA-448) MARC11 1993 ELECTRONIC INDUSTRIES ASSOCIATION ENGINEERING DEPARTMENT Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reprodu
3、ction or networking permitted without license from IHS -,-,- E I A 448-LB 73 3234600 05054b7 T T 8 NOTICE ?IA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability a
4、nd improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of EIA from manufacturing or selling products not c
5、onforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than EIA members, whether the standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EIA
6、in accordance with the American National Standards Institute (ANSI) patent policy. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Recommended Standard or Publication. This EIA Standard is considered to have In
7、ternational Standardization implication, but the International Electrotechnical Commission activity has not progressed to the point where a valid comparison between the EIA Standard and the IEC document can be made. This Standard does not purport to address all safety problems associated with its us
8、e or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. Published by * ELECTRONIC INDUSTRIES ASSOCIATION 1993 Engineering Depar
9、tment 2001 Pennsylvania Ave. N.W., Washington, D.C. 20006 PRICE: Please refer to the current Catalog of EIA & JEDEC STANDARDS & ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1-800-854-7179) International (303-792-21 81) All rights reserved Printed in U.S.A. Copyright
10、 Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from IHS -,-,- . EIA 448-LB 93 3234600 0.505468 934 Th
11、is document i s copyrighted by the EL4 and may not be reproduced without Organizations may obtain permission to reproduce a limited through entering into a license agreement with the EM. ELA Engineering Publications Office 2001 Pennsylvania Ave., N.W. Washington, D.C. 20006 (202)457-4963 Copyright E
12、lectronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from IHS -,-,- 1. PURPOSE E I A 448-1B 93 W 3234600 050.
13、5469 870 W EIA-448-1 B Page 1 METHOD 15 CONTACT BOUNCE (From IA Standards Proposal No. 1832, formulated under the cognizance of the EIA P-13.3 Subcommittee on Sensitive, Pushbutton and Keyboard Switches.) NOTE: This Standard is Revision B of Addendum No. 1 to ElA-448, “Standard Test Methods for Elec
14、tromechanical Switches.“ The purpose of this test method is to determine the duration of contact bounce SO that it can be anticipated and provided for in user circuits. This phenomenon is defined as the random opening and closing of a switch contact that occurs after contact transfer caused by the s
15、witch mechanism. It i s measured from the moment of first closure (or opening) to the moment when the contacts reach a useful state of equilibrium. Logic circuits are particularly sensitive to the kinetic behavior of switching contacts. Unless designed appropriately, these circuits can be triggered
16、to produce spurious data as a result of contact bounce. 2. PROCEDURE 2.1 The switch shall be mounted by its normal mounting means to a structure of sufficient mass that it be considered resonance-free. 2.2 The test circuit shown in Figure 1, or an equivalent, shall be used for measuring contact boun
17、ce. Voltage and current values shall be as specified in the Detail Specification, but shall not exceed an open circuit voltage of 6 Vdc and test current of 100 mA f 5%. 2.3 The detection and display means (oscilloscope or equivalent) utilized in the circuit shall have bandwidth of 1 megahertz or gre
18、ater, a minimum time base accuracy of 2 5% and shall be capable of showing the quiescent contact state prior to contact opening or closing. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie
19、Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A 448-LB 93 m 3234600 0505470 592 m EIA-448-1 B Page 2 2.4 The switch mechanism that causes contact transfer shall be actuated at a velocity as follows, unless otherwise specified in the
20、 Detail Specification: (a) Sensitive Switches 25 mm/s Max. (1.0 in/s Max.) (b) Nonsensitive Pushbutton 76 to 127 mm/s Switches (3 to 5 in/s) (c) Key Switches 381 f 254 mm/s (15k 10 in/s) (d) Rotary and Thumbwheel Switches 2 f 1 rad/s (e) Toggle and Rocker Switches 76 to 127 mm/s (3 to 5 in/s) 2.5 Wh
21、en contact bounce is affected by actuation force, the limits of force shall be specified in the Detail Specification. 2.6 The specified contact bounce duration shall be the maximum measurement occurring in five consecutive readings of switch closures or switch openings. Contact bounce at switch clos
22、ure is defined as the interval between switch actuation and switch closure (see Figure 2). Switch actuation occurs when measured voltage is 90% of the open circuits voltage. Switch closure occurs when the measured voltage remains less than 10% of the open circuit voltage. Contact bounce at switch op
23、ening is defined as the interval between switch deactuation and completion of switch opening (see Figure 2). Switch deactuation occurs when the measured voltage is 10% of the open circuit voltage. Switch opening is completed when the measured voltage remains greater than 90% of the open circuit volt
24、age. Voltage variations occur:ing after completion of switch closure or before switch opening are caused by variations in dynsmic contact resistance. An example of a typical recording of contact bounce is shown in Figure 2. Copyright Electronic Components, Assemblies & Materials Association Provided
25、 by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A 448-LB 93 m 3234600 0505471 429 m EIA-448-1 B Page 3 3 . SUMMARY The following details shall be spec
26、ified in the Detail Specifications: 3.1 The test circuit if other than as specified in 2.2. 3.2 The test load if other than as specified in 2.2. 3.3 Actuation rate if other than as specified in 2.4. 3.4 Actuation force when applicable. 3.5 Maximum allowable contact bounce duration at contact opening
27、 or closing or both opening and closing. Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from
28、 IHS -,-,- EIA-448-1B . Page 4 E I A YYB-LB 93 W 3234b00 0505Y72 3b5 W RESISTOR POWER SOURCE o I DETECTION ANO DISPLAY MEANS TEST $ 7 SWITCH FIGURE I CONTACT BOUNCE TEST CIRCUIT OPEN CIRCUIT VOLTAGE 1- FFECTS OF DYNAMIC CONTACT RESISTANCE. CONTACT BOUNCE -L, - - - 90% SWITCH CLOSURE SWITCH IO% -II c
29、- FIGURE 2 TYPICAL CONTACT BOUNCE TRACE OPENING Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 20:16:09 MDTNo reproduction or networking permitted without license from IHS -,-,-