The impedance of a circuit placed across a 120 V, 50 Hz (10 + j20). Find the current.
The impedance of a circuit placed across a 120 V, 50 Hz (10 + j20). Find the current.
Right Answer is:
2.4 – j4.8)A
SOLUTION
Current in the circuit = Voltage / Load impedance
I = V/Z
$\begin{array}{l} \dfrac{{120}}{{10 + j20}}\\ \\ = \dfrac{{120}}{{10{\rm{\;}} + {\rm{\;}}j20}} \times \dfrac{{(10{\rm{\;}} – {\rm{\;}}j20)}}{{(10{\rm{\;}} – {\rm{\;}}j20)}}\\ \\ \dfrac{{(1200{\rm{\;}} – {\rm{\;}}j2400)}}{{100{\rm{\;}} + 400}}\\ \\ \dfrac{{12}}{5} – \dfrac{{24j}}{5} \end{array}$
I = 2.4 – j 4.8 A