7
Impedance
The total opposition current flow a. current capaci-
tive circuit.05H.
∴ Ω
XL 3. circuit called impedance
and given the symbol Thus impedance the combined opposition to
current flow the resistance, inductive reactance and capacitive reactance
of the circuit and can calculated from the formula:
Z )
Ω
or
Z
V
I
T
T
Definition
The total opposition current flow in
an a.c.2
Ω
For inductive reactance:
X fL
L 2π
where 50Hz and 0. given the formula:
X
fC
C )
1
2π
Ω
where and are defined before and the capacitance the circuit.Baisc Electrical Installation Work
196
Capacitive reactance (XC) the opposition a.05H inductor they were separately
connected the 50Hz mains supply.c.
Example
Calculate the reactance 150μF capacitor and 0.
For capacitive reactance:
2
C
X
fC
1
π
where 50Hz and 150μF 150 106
F.
. causes the current the circuit lead ahead the voltage,
as shown Fig.
It can also expressed as:
X
V
I
C
C
C
Definition
Capacitive reactance (XC) the oppo-
sition a. 10.c.
∴ 6
1
2 3. causes the current the cir-
cuit lead ahead the voltage.2. circuit called impedance and
given the symbol Z.142 50Hz 150 F
21.05H 15. current capacitive
circuit.c.142 50Hz 0
