51 Ch26 DC Circuits

7/17/2019 51 Ch26 DC Circuits

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• Series and parallel resistors• Kirchhoff’s Rules for network problems

• Electrical meters and household circuits

• R-C circuits

DC CIRCUITS: Chapter 26

C 2012 ! "ecker



#earnin$ %oals - we will learn&•

'ow to simplif( resistors connectedin a circuit in series and in parallel! • 'ow to simplif( and anal()e more

complicated networks usin$Kirchhoff’s Rules! • R-C circuits



Series connection

Parallel connection

Resistors connected in a circuit in series orparallel can be simplified usin$ the followin$&



C 1**+ ,c-ermott. et al!. /rentice 'all

Calculate the total resistance of each bo if

each bulb has a resistance of 1000 hms Ω

3!



,ethod of simplif(in$ the circuit in a3 belowto $et the e4ui5alent resistance!

6e can then calculate the power / 7 82 Rdissipated in each resistor!



Eercise 29!1:& ;our e4ui5alent li$ht bulbsR1 7 R2 7 R3 7 R4 7 <!=0 Ω. emf 7 *!00 >olts!

;ind current and power in each li$ht bulb!6hich bulb is bri$htest?

#ater. if bulb @< is remo5ed which bulbs

$et bri$hter? immer?



n the course website. see old Aest @1from pre5ious semesters

for t(pical C circuit problems

B other t(pical problems on testsD

See

www!ph(sics!ssu!eduF"eckerFph(sics=1



Ahese comple circuits cannotbe reduced to series G

parallel combinations!

So use Kirchhoff’s Rules&

Σ I j = 0 unction rule5alid at any unction3Hconser5ation of char$e

2 Σ ∆! j " = 0 loop rule5alid for any closed loop3Hconser5ation of ener$(



Bt node B. Σ 8in 7 Σ 8out

81 I 83 7 82

Σ !rises = Σ !drops#oop @1&

82R2 Iε4I 81R1 7 ε1 I ε2

#oop @2&

ε3 I ε2 7 82R2 I 83R3

• #abel&: 8’sH

IF- on R’sHloops!

• 6rite e4uations!



Figure 26.66

5.00 A = 8

4.0

0

"

83

82

#abel the : branch currents 82. 83. and 84!

Since >#$ across all : branches is the same and

is known& >4 7 84R4 7 =B <Ω3 7 20 >olts.

the currents and ε can be readil( sol5ed!

B



>4 7 84R4 7 =B <Ω3 7 20 >olts

83 7 >3 F R3 7 <> F :Ω

7 1!:: B

Bt unction ". Σ 8 in 7 Σ 8 out

84 7 82 I 83 H 82 7 84 G 83 7 =B - 1!:B

82 7 :!JB

#oop @1& Σ > rises 7 Σ > dropsε 7 82R2 I 84R4 7 :!JB 2Ω3 I =B<Ω3

ε 7 2J!< >



>4 7 84R4 7 =B <Ω3 7 20 >olts

83 7 >3 F R3 7 <> F :Ω 7 1!:: B

Bt unction ". Σ 8 in 7 Σ 8 out84 7 82 I 83 H 82 7 84 - 83 7 =B - 1!:B 7 :!JB

#oop @1&Σ

> rises 7Σ

> drops

7 I 7 I 7

5.0 A

4.0

0

B

83

82



Figure 26.11

A(po on top of pa$e +*0 12th Edition3. 2nd line from top of pa$e&

ri$ht sideL should read bottomLSee ;i$ure 29!11 which is rotated *0o

from fi$ure in the 11th Edition!3



E#ECAR8CB# ,EBSMR8% 8SARM,EAS G,EAERS

B d’Brson5al $al5anometer meter mo5ement



B,,EAERS ha5e a 5er( small shunt resistor in themto reduce the effect of introducin$ the meterresistance into the circuit bein$ measured!

>#A,EAERS ∆>3 ha5e a 5er( lar%e series resistorin them to reduce the amount of current drawn fromthe circuit bein$ measured!



•8SC'BR%8%& C'BR%8%&

•Bn RC circuitthat can be usedto char%e an&&ischar%e a

capacitorthrou$h aresistor3!



•C'BR%8% B CB/BC8AR&

current 5s time

•C'BR%8% B CB/BC8AR&char$e 5s time



•8SC'BR%8% B CB/BC8AR&current 5s time

•8SC'BR%8% B CB/BC8AR&

char$e 5s time



o

o



•A battery, a capacitor, and a resistor are connected in series.

Which of the following affect(s) the maximum charge stored

on the capacitor?

•Q26.26

•A. the emf ε of the battery

•B. the capacitance C of the capacitor

•C. the resistance R of the resistor

•D. both ε and C

•E. all three of ε , C , and R



'ouse wirin$ circuits

' d d ill i i i h d i f



'and drill circuit with $round wire forsafet(



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C 2012 ; "ecker

51 Ch26 DC Circuits

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