# Impedance in polar form

1. Nov 14, 2012

### Michael V

1. The problem statement, all variables and given/known data

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.

2. Relevant equations

ZT = (Z1 × Z2)/(Z1 + Z2)

3. The attempt at a solution

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

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Last edited: Nov 14, 2012
2. Nov 14, 2012

### Staff: Mentor

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 Zp and Z3). Apply Ohm's law.

3. Nov 14, 2012

### 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.

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4. Nov 14, 2012

### Staff: Mentor

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.

5. Nov 14, 2012

### Michael V

I see. Thanks for your help.