Digital Signal Processing Reference
In-Depth Information
5 basic rules of electro technology
In physics, there are but 3 basic (linear) electrical components :
Resistance of OHM Inductance Capacitance
C
R
L
•
many complex circuits consist of interconnections of these three component
s
•
for example , you can show a (long) conductor as a substitute schematic like this :
L´
L´
L´
L´
R´
R´
R´
R´
C´
C´
C´
C´
R´, L´ and C´ are the correlative values per km circuit length
Current I and voltage U are the measurable effects of the electromagnetic field
. For this component ,
the following laws are valid :
R
U
u
I
I
=
bzw.
i
=
(instantaneous values)
OHM `s law
R
R
U
L
di
uL
1
=
³
i
=
bzw.
i
u t
Law of induction
L
dt
L
u
The faster the current alters in the coil, the higher the induced voltag .
C
du
1
i
=
³
i
=
C
bzw.
u
i
t
Law of capacitance
C
C
dt
C
u
The faster the capacitor´s voltage alters, the higher is the current flowing into or out of i.
The interconnection of several components in most cases happens as
Series connection
,
Parallel connection
e.g.
Multiple connection
R
1
R
2
U
1
U
2
I
2
U
3
I
1
R
1
U
U
2-3
I
2
R
1
R
2
R
3
U
1
I
3
R
2
R
3
I
I
I
U
U
U
Conductance
111
GGG
=+
RRRR
U
=++
RR
⋅
U
ges
1
2
ges
1
2
3
RR
=+
2
3
;
I
=
ges
1
R
+
R
R
=+
1
1
ges
I
=
U
=
I
⋅
R
usw
.
RRR
1
1
R
UU U
UU U
UI
=⋅
R U
;
=
UU
-
ges
1
2
ges
1
1
2
−
3
1
UIR
=⋅
=+
=⋅
IR IR
I
=
⋅
=+
−− − =
+
Ubzw
U
.
U
U
ges
11
2 2
I
=
;
I
=
1
2
3
23
−
23
−
II I
bzw.
II
−−
=
0
2
3
R
R
0
1
2
1
2
2
3
1
2
3
Kirchhoff´s first rule :
In a node (junction) in an electrical circuit, the sum of currents flowing into that node is equal
to the sum of currents flowing out of that node. Considering the current direction, you can also say: in a node, the sum
of all currents is zero. Behind this is the principle of charge conservation in physics(“Charges don´t duck out and do
not vaporize”).
Kirchhoff´s second rule :
“mesh rule”. In a mesh, that is one loop in a circuit from point A back to point A, the sum of
all voltages is zero . Behind this is the principle of energy conservation in physic. U = W/Q (Voltage is equal to energy
per unit charge). As the serial connection above show: there´s only as much energy transformed to heat by the
resistors as the voltage source provides.
Illustration 308:
Rules for the calculation of linear electro-technical circuits
Electro- technology basically describes practical applications of the electromagnetic field. Components
such as coil/ inductance L and conductor/ capacitance C can be assigned to this electromagnetic field.
Because of the current flow in conductive substances, electromagnetic energy is transformed into heat.
Representative of this process is the component OHM´s resistance R.
