Calculating Impedance and Power in AC Circuits

[Michael V]

Homework Statement

An impedance 8 + j7 Ω is connected in parallel with another impedance of 5 + j6 Ω. this circuit is then connected in series with another impedance, comprising a resistance of 5 Ω in series with a capacitive reactance of 7 Ω. The complete circuit is then connected to 150 volt, 50 hertz supply.

Calculate the following:

1. The supply current
2. The circuit power factor
3. The potential drop across each circuit.

Homework Equations

Z_T = (Z₁ × Z₂)/(Z₁ + Z₂)

The Attempt at a Solution

I attached my attempt. Having trouble with question 3. Potential drop?

 

[gneill]

You should keep a few more digits in your intermediate results; roundoff error is creeping into your significant figures as you go further into the calculations.

For potential drop, you have the current and the impedance of each of the series circuit 'blocks' (your Z_p and Z₃). Apply Ohm's law.

 

[Michael V]

OK, will do. So the potential drop is the same as voltage drop or potential difference? I attached my last answer, does it look ok? Thanks for help.

 

[gneill]

OK, will do. So the potential drop is the same as voltage drop or potential difference? I attached my last answer, does it look ok? Thanks for help.

Yup. And you're method's fine.

It's not clear to me from the problem statement whether you need to find the potentials across the individual components of the series circuit z3, too; While parallel components always share the same potential difference, series ones share the same current but have different potential differences.

 

[Michael V]

I see. Thanks for your help.