{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Electromagnetism- AC circuits

# Electromagnetism- AC circuits - Chapter 35 AC...

This preview shows pages 1–7. Sign up to view the full content.

Chapter 35: AC Circuits (Knight: 35.1-3) B x . F F θ θ μ B U - = μ B × = μ τ AI = μ

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Physics 113 Dr. Renat Letfullin 2 Today... AC Sources and Phasors Resistor Circuits Examples Capacitor AC Circuits (1) Capacitive Reactance Examples Voltage Dividers Analyzing a RC Circuit Filters and Transmission
Physics 113 Dr. Renat Letfullin 3 AC Sources and Phasors You can think of an AC generator as a battery-like object with an emf that varies sinusoidally as E (t) = E 0 cos ϖ t , where E 0 is the maximum emf and ϖ is the angular frequency, with ϖ =2 π f , where f is the frequency in Hz. Alternatively, the emf and other oscillatory quantities can be represented by a phasor diagram . The phasor is a vector of length E 0 that rotates counterclockwise around the origin with angular frequency ϖ , so that the angle it makes with the horizontal axis at any time is ϖ t . The projection of the phasor on the horizontal axis at any time gives the emf.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Physics 113 Dr. Renat Letfullin 4 Clicker Question 1 The instantaneous value of the emf E represented by this phasor is: (a) Increasing; (b) Decreasing; (c) Constant; (d) It is not possible to tell without knowing t .
Physics 113 Dr. Renat Letfullin 5 Resistor Circuits Consider an AC current i R through a resistor. Ohm’s Law gives the potential drop across the resistor, which we will call the resistor voltage v R . R R v i R = If the resistor is connected in an AC circuit as shown, then Kirschoff’s loop law tells us that: 0 soruce R R V V v + ∆ - = =E 0 ( ) cos R t t v ϖ = = E E 0 cos cos R R R v i t I t R R ϖ ϖ = = = E In the phasor diagram, the phasors for v R and i R are parallel.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Physics 113 Dr. Renat Letfullin 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}