dc circuits dc circuits • kirchoff’s laws • simple series
TRANSCRIPT
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
DC
Circuits
•C
ircu
it e
lem
en
ts–
Idea
l po
wer
& w
ires &
mete
rs, sw
itches, R
, C
•K
irch
off
’sla
ws
•S
imp
le s
erie
s &
pa
ralle
l circu
its
•R
C c
ircu
it
•E
xa
mp
les
•B
atte
rie
s–
inte
rnal re
sis
tance, d
ischarg
e
–energ
y s
tora
ge
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Circuit e
lem
ents
resis
tors
∆ ∆∆∆V
= IR
cap
acit
or
∆ ∆∆∆V
= Q
/C
V -
ide
al
vo
lta
ge s
up
ply
(id
ea
l b
att
ery
)
sw
itc
h
op
en
/clo
se
ideal
wir
es
(R
= 0
)
carr
y c
urr
en
t I
wit
h n
o v
olt
ag
e d
rop
no
de -
cu
rren
t d
ivid
es
vo
lta
ge c
om
mo
n
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Kirchoff’s
rule
s
1.
Ch
arg
e C
on
se
rva
tio
n:
su
m o
f a
ll cu
rre
nts
in
to a
no
de is
ze
ro.
2.
En
erg
y c
on
se
rva
tio
n:
su
m o
f vo
lta
ge
ch
an
ge
s a
rou
nd
circu
it is z
ero
.
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Sim
ple
para
llel circuits
I=
I 1+
I 2
=Q° 1
+Q° 2
toy
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Sim
ple
series c
ircuit
DV=D
V1+D
V2
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
RC
circuit -
charg
e
toy
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
RC
circuit -
dis
charg
e
toy
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Exam
ple
s o
f K
irchoff
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Anoth
er:
P28.2
8
me
sh
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
26.7
6
•D
or
(D-d
)
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
12 V
ä 8
0 A
mp-h
r
> 1
2 V
ä 3
00,0
00 C
= 3
.6 1
06J
= 9
60 W
-hr >
1 k
W-h
r (~
10 c
ents
)
Batteries
•A
“b
atte
ry”
of
Le
yd
en
jars
(ca
pa
cito
rs)
•B
atte
ry s
up
plie
s c
urr
ent
at
ne
arly c
on
sta
nt vo
lta
ge
, V
.
–In
tern
al re
sis
tance
–D
ischarg
e c
urv
e
•T
ota
l cha
rge
Q
= I t
•T
ota
l en
erg
y
U =
Q V
e
.g.
toy
pd
f
Phys
208,
Fall
2006
Oct
. 9, 2006
DC
Cir
cuit
s
Battery
dis
charg
e