52
A
A
X
X
4
4
T
T
I
I
I
I
-
-
5
5
3
3
3
3
/
/
A
A
X
X
4
4
T
T
I
I
I
I
-
-
5
5
3
3
3
3
N
N
O
O
n
n
l
l
i
i
n
n
e
e
M
M
a
a
n
n
u
u
a
a
l
l
L
L
o
o
w
w
E
E
S
S
R
R
C
C
a
a
p
p
a
a
c
c
i
i
t
t
o
o
r
r
A group of large capacitors that meet the requirements of today’s high performance motherboard design. The theory behind this
is long transmission lines have considerable inductance and capacitance as well as resistance. When a current flows through
the line, inductance and capacitance have the effect of varying the voltage on the line as the current varies. Thus the supply
voltage varies with the load. Several kinds of devices are used to overcome this undesirable variation, in an operation called
regulation of the voltage. They include induction regulators and three-phase synchronous motors (called synchronous
condensers), both of which vary the effective amount of inductance and capacitance in the transmission circuit. Inductance and
capacitance react with a tendency to nullify one another. When a load circuit has more inductive than capacitive reactance, as
almost invariably occurs in large power systems, the amount of power delivered for a given voltage and current is less than
when the two are equal. The ratio of these two amounts of power is called the power factor. Because transmission-line losses
are proportional to current, capacitance is added to the circuit when possible, thus bringing the power factor as nearly as
possible to 1. For this reason, large capacitors are frequently inserted as a part of power-transmission systems.
