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I have this circuit and I need to calculate the total complex impedance.

enter image description here

Note: the \$r\$ is internal resistance of the coil so how can we calculate the complex impedance?

The coil and the resistance \$R\$ are in parallel.

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    \$\begingroup\$ If you want a numerical answer you need to provide the operating frequency of the circuit. Do you understand complex numbers to any degree? \$\endgroup\$
    – Andy aka
    Commented Mar 10, 2021 at 11:12
  • \$\begingroup\$ @Andyaka yes the frequency of the circuit is 50 Hz , i want to know how can i calculate the complex impedance with this internal resistance r of the coil , \$\endgroup\$ Commented Mar 10, 2021 at 11:24

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Well, the impendance of this circuit is given by:

$$\underline{\text{Z}}_{\space\text{in}}=\text{R}\text{||}\left(\text{r}+\text{j}\omega\text{L}\right)=\frac{\text{R}\left(\text{r}+\text{j}\omega\text{L}\right)}{\text{R}+\text{r}+\text{j}\omega\text{L}}\tag1$$

Using the numbers, we get:

$$\underline{\text{Z}}_{\space\text{in}}=\frac{220\left(100+\text{j}\cdot2\pi\cdot50\cdot550\cdot10^{-3}\right)}{220+100+\text{j}\cdot2\pi\cdot50\cdot550\cdot10^{-3}}=$$ $$220-\frac{619520}{4096+121 \pi ^2}+\frac{106480 \pi \text{j}}{4096+121 \pi ^2}\approx102.893+63.233\text{j}\tag2$$

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    \$\begingroup\$ thanks @Jan for helping me! \$\endgroup\$ Commented Mar 10, 2021 at 11:31
  • \$\begingroup\$ @IsmailBenyoub You're welcome! \$\endgroup\$ Commented Mar 10, 2021 at 11:32

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