TABLE OF CONTENTS Sooner or later, in any text on magnetics, the subject of units of measurement must be considered. The author regrets having to introduce the matter, because three different systems of units are in general use. Physicists may prefer CGS units, engineers in general use MKS units, and transformer designers use English units. The international standard (SI) is the MKS system, and usage trends toward this system. Table 7.5 summarizes the present situation in magnetics units, and this table may serve either as a handy reference for the reader or a page to be torn out to line the bird cage.
| MKS (SI) Units | CGS Units | English Units | |
|---|---|---|---|
| Flux density | B = ? r ? oH | B = ? rH | B = ? r ? oH |
| Flux | ? = AB | ? = AB | ? = AB |
| Faraday's Law | v = Nd ?/ dt | v= 10 8 Nd ?/ dt | v = 10 8 Nd ?/ dt |
| ? o | 4 ? 10 7 | 1.0 | 3.192 |
| Units | A in m 2 | A in cm 2 | A in in 2 |
| B in teslas | B in gauss | B in lines/in 2 | |
| H in amp turns/m | H in oersteds | H in amp turns/in | |
| ? in webers | ? in maxwells | ? in lines | |
| F in amp turns | F in gilberts | F in amp turns |
