IEEE Std 945-2019 pdf free download – IEEE Recommended Practice for Preferred Metric Units for Use in Electrical and Electronics Science and Technology.
1. Overview
1.1 Scope
This rcommended practice provides the prefered metrie units for use in Eletrica and Electroniss Science and Technology and supports the aplication of IEEE/ASTM SI 10.
1.2 Purpose
The purpose of this reommended pactice is 阳aid in the selection of appropriate metrie units for quanties that are of interst to elctrical and electronic engineers.
2. Normative references
The fllowing referenced documents are indispensable for the application of this document (i.e, they must be undarstood and used. so each referenced document is cied in text and its relationship to this document is explained). For dated rferencs, only the edition cited applies. For undated rfercnces, the lates edition of the referenced document (including any amendments or crrigendnd applies.
IEEE/ASTM SI 10M, American National Standard for Metrie PraticeL1
3. Definitions
For the puposs of this document, the fllowin terms and dfitionrs apply. The IEEE Siandards Dictionery Online should be consulted for terms not defined in this clause.
area density: The quantity of mass per area.
coefficient of heat transfer: The density of heat flow rate divided by the temperature difference.
density: The quantity of mass per volume.
linear densit: The quantity of mass per length.
mass concentration: The quantity of mass of a constituent per volume of the mixture.
thermal insulance: The termperature difference divided by density of heat flow rate.
thermal resistance: The temperature difference divided by heat flow rate.
NOTE- Cofficient of heat transfer and thermnal insulance are reeiprocals of cach other.+
4. Multiples and submultiples of SI units
For SI prefixes, symbols, and multiplication factors, see IEEE/ASTM SI 10.
A common practice is to use multiples and submultiples that are a powers of 10, also known as the rule of 1000.
5. Space and time
Table 1 provides preferred space and time SI units.IEEE Std 945 pdf download.