ASTM B77-81(1994)e1

Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys

SCOPE
1.1 This test method covers the determination of the thermoelectric power of a metal or alloy with respect to copper when the temperatures of the junctions lie between 0 and 100oC.
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.  
1.3 The values stated in inch-pound units are the preferred unit. The values in parentheses are for information only.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.10 - Thermostat Metals and Electrical Resistance Heating Materials

Relations

• Replaced By: ASTM B77-81(2001) - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-Jan-2001

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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
e1
Designation: B 77 – 81 (Reapproved 1994) An American National Standard
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
Thermoelectric Power of Electrical-Resistance Alloys
This standard is issued under the fixed designation B 77 ; 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.
e NOTE—Section 10 was added editorially in June 1994.
1. Scope which a low thermoelectric power is desired. As most electric
circuits are largely composed of copper, the thermoelectric
1.1 This test method covers the determination of the ther-
power of a resistance metal will generally be measured against
moelectric power of a metal or alloy with respect to copper
copper.
when the temperatures of the junctions lie between 0 and
100°C.
5. Test Specimen
1.2 This standard does not purport to address all of the
5.1 The metal or alloy to be tested shall be in the form of
safety concerns, if any, associated with its use. It is the
sheet, ribbon, or wire and the test specimen shall be of such
responsibility of the user of this standard to establish appro-
length that the two ends can be readily maintained at different
priate safety and health practices and determine the applica-
temperatures. At each end of the specimen a copper lead of
bility of regulatory limitations prior to use.
convenient size shall be fastened. These leads shall make good
1.3 The values stated in inch-pound units are the preferred
electrical contact with the specimen, such as that obtained by
unit. The values in parentheses are for information only.
welding, brazing, or soldering. Slight impurities in the copper
have a negligible effect on the thermoelectric power.
2. Referenced Documents
2.1 ASTM Standards: NOTE 1—When necessary to specify the quality of the copper leads,
reference should be made to Specification B 3.
B 3 Specification for Soft or Annealed Copper Wire
6. Procedure
3. Terminology
6.1 Measurement of Temperature—As a matter of
3.1 thermoelectric power, Q—the electromotive force in an
precaution, the average temperature used in determining the
electric circuit consisting of two metals when the junctions
thermoelectric power shall be approximately the same as that
between them have a difference in temperature of 1°C.
to which the material will be subjected in practice, and in no
3.1.1 Discussion—Experimentally, it has been found that
case shall the temperature difference between the two junctions
the thermoelectric power of two metals is not a constant but
be less than 20°C. The temperature at each of two junctions
depends on the mean temperature of the junctions. However,
shall be measured by a device that is sufficiently accurate to
over a range of temperature from 0 to 100°C it is usually
determine the temperature difference within 5 %. A convenient
sufficient to assume that the thermoelectric power is indepen-
method for determining the temperatures of the junctions is to
dent of temperature so that for this range of temperature:
immerse each junction in separate oil baths maintained at the
Q 5 E/~t8 2 t!
desired temperatures. Baths that are stirred and the
temperatures of which are thermostatically controlled are to be
where:
preferred. However, beakers of oil which are supported by
E = the electromotive force developed in the circuit,
blocks of metal, sand baths, or other means may be used,
t8 = the higher temperature at one junction, °C, and
provided the thermal capacity of these assemblies is such that
t = the lower temperature at the other junction, °C.
when the heat is cut off their temperatures will decrease at rates
less than 0.2°C/min. The temperature of the oil in each bath
4. Significance and Use
may be determined either by a calibrated mercury thermometer
4.1 The purpose of this method is to determine the
or by a calibrated thermocouple
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