scope:

Foreword

This standard was developed from three separate standards, ASA Z10.5-1949, Letter Symbols for Electrical Quantities, ASA Y10.9-1953, Letter Symbols for Radio, and 57IRE21S1, Letter Symbols and Mathematical Signs. The first edition of this standard was issued as USAS Y10.5-1968 IEEE Std 280-1968, Standard Letter Symbols for Quantities Used in Electrical Science and Electrical Engineering. In the development of this standard the International Electrotechnical Commission Publication 27, Letter Symbols to be Used in Electrical Technology, has been followed closely.

In this revision the following changes and additions have been made:

1) A new section, Scope, has been added.

2) A new section, References has been added.

3) Section 3.2 on typography has been expanded and clarified.

4) Text concerning unit symbols has been expanded and text on the SI system of units added; these now parallel the statements in ANSI/IEEE 268-1982 , American National Standard Metric Practice. All units (for example, temperature, pressure, conductance) have been revised to agree with current SI practice.

Celsius temperature replaces the former terms temperature and customary temperature

Reciprocal degree Celsius replaces reciprocal kelvin

References to cycle per second have been deleted

In Table 6, 6.59, Subscripts, Semiconductor Devices, the terms drain terminal and source terminal were added.

In Table 8 the values of the physical constants have been revised to agree with current information.

Attention is called to the following related standards:

ANSI Y10.20-1975, Mathematical Signs and Symbols for Use in Physical Science and Technology.

ANSI/IEEE Std 260-1978, IEEE Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units).

ANSI/IEEE Std 268-1982, American National Standard Metric Practice.  

Scope

This standard covers letter symbols used to represent physical quantities in the field of electrical science and electrical engineering. These symbols are independent of the units (see ANSI/IEEE Std 260-1978 [2]¹) employed or special values assigned. Also included are selected symbols for mathematics and for physical constants.