Phy122_0930 - ch. 19

Phy122_0930 - ch. 19 - Physics 122 Sept 30 2010 Starting...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Physics 122 Sept. 30, 2010 Starting chapter 19. This material will not appear on your 1 st midterm exam. yu r mr mm . October 4. Review session: Javits 103, 6:50-8:50 PM ctober 5 Second lecture on Ch 19 October 5. Second lecture on Ch. 19 October 5. 8:30-10:00 PM Midterm exam on Ch. 15-18. Last names beginning A-J: Old Engineering 145 Last names beginning K-Z: Old Chem. 116 Bring a calculator, pencils, erasers, 1 8½” x 11” page of notes (both sides OK). October 6. 5:00 PM. HW on Ch. 19 is due. Question 1:
Background image of page 1

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

View Full DocumentRight Arrow Icon
Resistor Capacitor circuits. apacitor initially uncharged is Capacitor, initially uncharged, is charged through a resistor once the switch is closed. he voltages across each The voltages across each component and the current in the circuit have an exponential time dependence. I(t) = V Batt R e t / RC (t) = / C = (1 / ) t / RC(dimensionless) Æ
Background image of page 2
Question 2: If the time onstant of the top constant of the top circuit is 1 msec., what is the time onstant of the constant of the bottom circuit? (Each R and each C is identical to the nes in the top ones in the top circuit.)
Background image of page 3

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

View Full DocumentRight Arrow Icon
Question 2: f the time If the time constant of the top circuit is 1 msec., what is the time constant of the bottom circuit? R bottom = R top / 3 3 C bottom = 3 C top So R bottom bottom = R top top
Background image of page 4
I(t) = V Batt R e t / RC / (t) C = (1 / ) uestion #3 In an RC circuit with 100 Volts C = Question #3 : In an RC circuit with V batt = 100 Volts, C = 1 μ F, R = 100 , what is the capacitor voltage 100 μ sec after the switch is closed?
Background image of page 5

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

View Full DocumentRight Arrow Icon
Question #3: In an RC circuit (R = 100 Ohm, C = 1 μ F, V = 100 Volts what is the capacitor voltage 100 ec 100 Volts ) , what is the capacitor voltage 100 μ sec after the switch is closed? V ap = 100 (1 - e - t / RC ) cap t/RC= 1.0x10 -4 / (100 x 1x10 -6 ) = 1 100 (1 – -1 = 100 (1 – 368) = 63 2 Volts cap = 100 (1 e ) = 100 (1 0.368) = 63.2 Volts After 200 μ sec (total), t/RC = 2, cap = 100 (1 – e -2 ) = 100 (1 – 0.136) = 86.4 Volts After 300 μ sec (total), t/RC = 3, cap = 100 (1 – e -3 ) = 100 (1 – 0.0498) = 95.0 Volts
Background image of page 6
You can also go the other way. Given the desired value, V R (t) / V Batt , find t/ R C. V (t)/V = e t / RC / ln[V (t) /V ] = ln[e ] = t/RC o take the
Background image of page 7

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

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 10/18/2010.

Page1 / 26

Phy122_0930 - ch. 19 - Physics 122 Sept 30 2010 Starting...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online