2. Darryl Michael/GE CRD Fields and Waves Lesson 4.7 MAGNETIC CIRCUITS

3. Introduction MAGNETIC CIRCUITS used to analyze relays, switches, speakers... In Lesson 4.6 experiment: R coil not wound symmetrically Flux stayed in TOROID did not detect with external loop

4. Magnetic Flux - TOROID Flux is a constant = Flux stays in toroid - so area is a constant B and H are constant along the path Problem 1 - has square material - get H and B, then get Flux and L Do Problem 1a and 1b

5. Magnetic Flux - TOROID with GAP Add gap to toroid: g Apply boundary conditions across gap: Can get very large H in gap Gap has very strong effect on H

6. Magnetic Circuits - Analogy to E-circuits Magneto -motive force Reluctance of iron Reluctance of gap enables us to draw analogy to electric circuits

7. Magnetic Circuits & Electric Circuits Electric Circuits Magnetic Circuits V or e.m.fNI or m.m.f I Magnetic circuits model: High  - low reluctance path Finish problem 1