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Ye olde capacitor 8.3. Instructor Course. Today & Beyond. Quiz Material on Capacitors not in the unit. Complete the unit (9) SPRING BREAK RETURN Monday – Begin Unit on Magnetism. (Bring to class) Wednesday – EXAMINATION #2 / Bring in units 4-9 / Lab Reports Due.
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Ye olde capacitor8.3 InstructorCourse
Today & Beyond • Quiz • Material on Capacitors not in the unit. • Complete the unit (9) • SPRING BREAK • RETURN • Monday – Begin Unit on Magnetism. (Bring to class) • Wednesday – EXAMINATION #2 / Bring in units 4-9 / Lab Reports Due. • Friday – Continue magnetism unit.
What is the current through the 4- resistor in this circuit? a) 0.67 A b) 0.75 A c) 1.0 A d) 1.5 A e) 4.5 A Text Answer
What's Happening? DIELECTRIC
Apply an Electric Field Some LOCAL ordering Larger Scale Ordering
Adding things up.. - + Net effect REDUCES the field
We can measure the C of a capacitor (later) C0 = Vacuum or air Value C = With dielectric in place C=kC0
Recall the experiment – • Voltage across C seemed to drop rather than stay stable. • You were given a second capacitor and it held it’s value. • What’s going on??? • meters have resistors of 1-10MW
20.13 RC Circuits Capacitor charging time constant
20.13 RC Circuits Capacitor discharging time constant
Stored Energy • Charge the Capacitor by moving Dq charge from + to – side. • Work = Dq Ed= Dq(V/d)d=DqV
A Thunker Find the equivalent capacitance between points a and b in the combination of capacitors shown in the figure. V(ab) same across each