Tài liệu Circuits & Electronics P12 pdf

6.002 Fall 2000 Lecture
1
12
6.002
CIRCUITS
AND
ELECTRONICS
Capacitors
and First-Order Systems
6.002 Fall 2000 Lecture
2
12
5V
0V
C
A
B
5V
A
B
C
5
0
5
0
5
0
Reading:
Chapters 9 & 10
Demo
5V

Expected
Observed
Expect this, right?
But observe this!
Delay!
Motivation
6.002 Fall 2000 Lecture
3
12
The Capacitor
G
D
S
n-channel MOSFET
symbol
n-channel
MOSFET
n-channel
s
i
l
i
c
o
n
n
m
e
t
a

l
+
+
+
+
+
+
o
x
i
d
e
drain
gate
source
C
GS
G
D
S
n
p
6.002 Fall 2000 Lecture
4
12
Ideal Linear Capacitor
obeys DMD!
total charge on
capacitor
0qq =−+=

d
EA
C =
+ +
+ + + +
--
-----
A
E
d
coulombs farads volts
vCq =
i
C
q
+
–
v
6.002 Fall 2000 Lecture
5
12
Ideal Linear Capacitor
dt
dq
i
=
( )
dt
Cvd
=

dt
dv
C
=
i
vCq
=
C
q
+
–
v
A capacitor is an energy storage device
Æ memory device Æ history matters!






=
2
2
1
CvE