Theory : Electricity
Lecture 1 :
·
66 % electronics ,
34 % photonics
3 hour written exam
-
Synthesis on 12
pages to bring
The industrial (1840- ) Transmission of power
age ... -
ex : evolution of the lightbulb
The information age (1971- ...
) - Transmission of information
evolution of the phone
flow
ex :
From electrons to
light (phostoms) a The
physics of electron strippe e
metal wire
chementte
Electron flow in copper wires :
[
·
alldirection on
The Bohr's model of the Copper atom :
The depends the of the
resistance on
resistivity material :
Resistance of the opposition that conductor offers to the of electric current (depends the
= a measure a
passage on
material's properties length ,
a cross-sectional area
Resistivity = a fundamental property of a material that quantifies how
strongly the material opposes the flow of
electronic current (expressed in ohm's meters 1 .
m) - low (Silverscopper) , high Crubber sulfur
A resistivity depends on temperature (higher temperature -
higher resistivity)
The drift speed of electrons :
u
=9
u = drift speed in mis A = cross section area of the wire in squared meter
I = current intensity in Ampere (CIs) a = carried
charge of one electron in Coulomb (C) .
n = nb of free electrons per cubic meter
,example exercise : At what speed do the electrons move inside the wire ?
1) How atoms in a ms of copper ?
many
density gl cons
Y
230 volts direct current -
= 3 94
.
so there are 140665 5 mallm
glma
.
,
·
atomic weight = 63 546
.
wire : 2 . 5 mm2 cross section area
" sow
light bulb 2) In one mole of
any element there are 6 .
622x10 atoms (Avogadro number
3) Therefore ,
in a ms of copper there are about 8 .
5 x102 atoms (6 022x104
.
10685 5)
.
4) Copper has one frer electron atom .
per
X
ampere-Watts/Vots The
charge of one electron is -1 .
6x10C .
601230
>
-
u =
(8 . 5 x 1028)(2 5/10004(1
. . 6 x 10
-
19)
u =
7 .
672634x10-6 m/S
U = 2 762148
.
colhour -+ electrons move inside the wire at about som/hour
&
I = electric current in
Amperes
The transmission speed with electrons >
- V = IR V = electric voltage in Volts
P = VI R = electric resistance in Ohms
P = electric power in Watts
Resistance is like logged with hair.
-
pushing water
through a pipe
Pressure les water les pressure
-
gives
Slow drift
electron pumped in
from
=> velocity vs near .
lightspeed signal velocity
electricity"
battery - -
The "Speed of
-
--
--
-
-
-
> 00000000000000+
--
-
↑ the
-
experiences force almost speed is not
-
super
-
instantaneously high but,
reaction is
almost instant
.
P
# => electric current (intensity) is the rate of the flow of positive
charges in the .
circuit (Ampères
on V => electric
positive
voltage (potential difference)
. (Volts
charges
is the "push" for the flow of
a
"Il
-
& => electric resistance of a circuit element is its opposition to the current
Cohms)
V = IR ↑ Is electric power is the rate at which electric energy is transferred by an
P = VI electric .
circuit (Watts)
·
law (kVL)
Kirchoff's Voltage
n
Kirchoff's Current law (k(L)
All potential differences (volts)
thecrent intensityenterinon
=>
to
around a
loop sum zero
.
that
current leaving junction. Vy = -
Vi -
Ve -
Vz
in + iy = iz + 13
Lecture 1 :
·
66 % electronics ,
34 % photonics
3 hour written exam
-
Synthesis on 12
pages to bring
The industrial (1840- ) Transmission of power
age ... -
ex : evolution of the lightbulb
The information age (1971- ...
) - Transmission of information
evolution of the phone
flow
ex :
From electrons to
light (phostoms) a The
physics of electron strippe e
metal wire
chementte
Electron flow in copper wires :
[
·
alldirection on
The Bohr's model of the Copper atom :
The depends the of the
resistance on
resistivity material :
Resistance of the opposition that conductor offers to the of electric current (depends the
= a measure a
passage on
material's properties length ,
a cross-sectional area
Resistivity = a fundamental property of a material that quantifies how
strongly the material opposes the flow of
electronic current (expressed in ohm's meters 1 .
m) - low (Silverscopper) , high Crubber sulfur
A resistivity depends on temperature (higher temperature -
higher resistivity)
The drift speed of electrons :
u
=9
u = drift speed in mis A = cross section area of the wire in squared meter
I = current intensity in Ampere (CIs) a = carried
charge of one electron in Coulomb (C) .
n = nb of free electrons per cubic meter
,example exercise : At what speed do the electrons move inside the wire ?
1) How atoms in a ms of copper ?
many
density gl cons
Y
230 volts direct current -
= 3 94
.
so there are 140665 5 mallm
glma
.
,
·
atomic weight = 63 546
.
wire : 2 . 5 mm2 cross section area
" sow
light bulb 2) In one mole of
any element there are 6 .
622x10 atoms (Avogadro number
3) Therefore ,
in a ms of copper there are about 8 .
5 x102 atoms (6 022x104
.
10685 5)
.
4) Copper has one frer electron atom .
per
X
ampere-Watts/Vots The
charge of one electron is -1 .
6x10C .
601230
>
-
u =
(8 . 5 x 1028)(2 5/10004(1
. . 6 x 10
-
19)
u =
7 .
672634x10-6 m/S
U = 2 762148
.
colhour -+ electrons move inside the wire at about som/hour
&
I = electric current in
Amperes
The transmission speed with electrons >
- V = IR V = electric voltage in Volts
P = VI R = electric resistance in Ohms
P = electric power in Watts
Resistance is like logged with hair.
-
pushing water
through a pipe
Pressure les water les pressure
-
gives
Slow drift
electron pumped in
from
=> velocity vs near .
lightspeed signal velocity
electricity"
battery - -
The "Speed of
-
--
--
-
-
-
> 00000000000000+
--
-
↑ the
-
experiences force almost speed is not
-
super
-
instantaneously high but,
reaction is
almost instant
.
P
# => electric current (intensity) is the rate of the flow of positive
charges in the .
circuit (Ampères
on V => electric
positive
voltage (potential difference)
. (Volts
charges
is the "push" for the flow of
a
"Il
-
& => electric resistance of a circuit element is its opposition to the current
Cohms)
V = IR ↑ Is electric power is the rate at which electric energy is transferred by an
P = VI electric .
circuit (Watts)
·
law (kVL)
Kirchoff's Voltage
n
Kirchoff's Current law (k(L)
All potential differences (volts)
thecrent intensityenterinon
=>
to
around a
loop sum zero
.
that
current leaving junction. Vy = -
Vi -
Ve -
Vz
in + iy = iz + 13
