Unit13Concepts - generator-like behavior by producing an...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
My Blackboard All Blackboard Sites Home Help Logout Course Map Announcements Course Info/Calendar Unit 10 Unit 11 Unit 12 Unit 13 Unit 14 Unit 15 Unit 16 Unit 17 Unit 18 all videos My Grades Unit 13. Time-Dependent Currents. Major Concepts Electromagnetic induction Electromagnetic induction is the phenomena in which an emf is induced in a coil of wire by a change in the magnetic Fux that passes through the coil. A motional emf Separated charges on the ends of a moving conductor give rise to an induced emf, called a motional emf , because it originates from the motion of the conductor. The magnetic Fux The Fux is proportional to the number of magnetic ±eld lines that pass through a surface. Lenz's Law The polarity of an induced emf is such that the induced current produces an induced magnetic ±eld that opposes the change in Fux causing the emf. A back emf When an electric motor is running, it exhibits
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: generator-like behavior by producing an induced emf, called a back emf or counter emf . Mutual induction Mutual induction is the effect in which a changing current in a primary coil induces an emf in a secondary coil. Self-induction Self-induction is the effect in which a change in current in a coil induces an emf in the same coil. A transfomer A transfomer is a device for increasing or decreasing an ac voltage. Transfomer property A transfomer that steps up the voltage simultaneously steps down the current, and a transformer that steps down the voltage steps up the current. The capacitive reactance V rms = I rms *X C The capacitive reactance - X C is measured in ohms and determines how much rms-current exist in a capacitor in response to a given rms-voltage across the capacitor. 1 of 1 5/16/09 12:51 PM...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online