MIL-STD-202H.pdf - 第281页
MI L - S TD - 202 - 30 9 5. DETAILED REQUI RE M E N T S 5.1. SUMM ARY. T he f ol l ow i ng det a i l i s t o be s p ec i f i e d i n t h e i nd i v i dua l s pec i f i c at i on: The continu o us w or k i ng v ol t ag e …
MIL-STD-202-309
METHOD 309
VOLTAGE COEFFICIENT OF RESISTANCE DETERMINATION PROCEDURE
1. SCOPE
1.1 Purpose. Certain types of resistors exhibit a variation of resistance with changes in voltage across the resistor.
This is a measurable characteristic; a test to determine the magnitude of such a characteristic is the Voltage
Coefficient of Resistance Determination Procedure.
1.2 Precautions. Adherence to 4.1, applying voltage intermittently for not more than the total of 0.5 seconds in any
5 second interval is emphasized as an important consideration of this method. Failure to comply would result in a
voltage coefficient of vast variations. A resistance measuring device capable of withstanding high voltage
applications should be used. Certain types of resistors exhibit a variation of resistance with changes in potential
difference, this effect being separate and distinct from the change in resistance due to heating effect whether from
applied voltage or ambient conditions.
2. APPLICABLE DOCUMENTS
This section not applicable to this standard.
3. DEFINTIONS
This section not applicable to this standard.
4. GENERAL REQUIREMENTS
4.1. Procedure. The voltage coefficient is applicable only to resistors of 1,000 ohms and over. Unless otherwise
specified in the individual specification, all measurements and tests shall be made at a temperature of 25°C ±5°C.
Adjust the resistance measuring device to apply 0.1 X rated continuous working voltage to the resistor. Measure the
resistance by applying this voltage intermittently for not more than the total of 0.5 second in any 5 second interval.
Readjust the resistance measuring device to apply 1.0 X rated continuous working voltage to the resistor and repeat
the above intermittent measuring procedure. Compute the Voltage Coefficient (VC) as follows:
Er
rR
VC
9.0
100)( −
=
Where:
R = Resistance at rated continuous working voltage.
r = Resistance at 0.1 rated continuous working voltage.
E = Rated continuous working voltage.
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MIL-STD-202-309
5. DETAILED REQUIREMENTS
5.1. SUMMARY. The following detail is to be specified in the individual specification:
The continuous working voltage (see 4.1).
6. NOTES
(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)
6.1 Supersession data. The main body and 38 parts of this revision of MIL-STD-202 replace superseded MIL-STD-
202.
Custodians: Preparing activity:
Army - CR DLA – CC
Navy - EC
Air Force - 85 (Project 59GP-2015-039)
DLA - CC
Review activities:
Army - AR, AT, AV, CR4, MI, SM, TE
Navy - AS, OS, SH
Air Force - 19, 99
NSA - NS
NOTE: The activities listed above were interested in this document as of the date of this document. Since
organizations and responsibilities can change, you should verify the currency of the information above using the
ASSIST Online database at https://assist.dla.mil/
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北测（上海）电子科技有限公司
联系方式：xuyj@beice-sh.com 13917165676
INCH-POUND
MIL-STD-202-310
18 April 2015
SUPERSEDING
MIL-STD-202G
w/CHANGE 2 (IN PART)
28 June 2013
(see 6.1)
DEPARTMENT OF DEFENSE
TEST METHOD STANDARD
METHOD 310, CONTACT-CHATTER MONITORING
AMSC N/A FSC 59GP
北测（上海）电子科技有限公司
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