Impedances of R, L, C, RL, RC, LC and RLC circuits

In summary, the conversation discusses three different equations for calculating impedance (Z) in circuits. The first equation is simply Z = R, where R represents the resistance in the circuit. The second equation is more complex and involves the use of imaginary numbers, with Z representing the inverse of the sum of all the individual impedances. The third equation provides a more detailed explanation of how to calculate impedance in both series and parallel circuits, using complex numbers and the formula Z = (Z1^-1 + Z2^-1 + ...)^-1.
  • #1
Bruno Tolentino
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Homework Statement


In first place, ignore the source in each circuit, ignore if make sense or not. I placed one sorce in each circuit just for the circuit be more visible.

In second place, ignore the numerical values of the sources, resistors, capacitors and inductors. Think R, L and C in place of numerical values.

So, my doubt is the following: given all these circuits, what is the equation of the impedeance (Z) in function of R, L and C?

01.png


02.png


03.png


Homework Equations

The Attempt at a Solution



1.1) Z = R
1.2)
1.3)

2.1)
2.2)
2.3)
2.4)
2.5)
2.6)

3.1) Z = R + i(ωL - (ωC)⁻¹)
3.2) Z = R⁻¹ + i(ωC - (ωL)⁻¹)
3.3)
3.4)
3.5)
3.6)
3.7)
3.8)
 
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  • #2
ZR = R
ZL = jωL
ZC = 1 / jωC = j / (j*j*ωC) = -j / ωC

In series you just add the impedances.
In parallel use: Z = ( Z1-1 + Z2-1 + . . . )-1

You must be able to calculate with complex numbers. Just remember that j2 = -1.

Try to calculate 3.1) and 3.2) yourself ( think you have read the answer somewhere ).
 
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1. What is an impedance in a circuit?

Impedance is the measure of opposition to the flow of an alternating current (AC) in a circuit. It is represented by the symbol Z and is measured in ohms.

2. How are resistors, inductors, and capacitors related to impedance?

Resistors, inductors, and capacitors all contribute to the overall impedance of a circuit. A resistor's impedance is solely determined by its resistance, while an inductor's impedance is proportional to the frequency of the AC and its inductance. A capacitor's impedance is inversely proportional to the frequency and directly proportional to its capacitance.

3. What is the difference between impedance and resistance?

The main difference between impedance and resistance is that resistance refers to the opposition to the flow of direct current (DC), while impedance refers to the opposition to the flow of AC. Resistance is a scalar quantity, while impedance is a complex quantity that takes into account both magnitude and phase.

4. How do I calculate the impedance of a series RL circuit?

To calculate the impedance of a series RL (resistor-inductor) circuit, use the formula Z = √(R² + (XL- XC)²), where R is the resistance in ohms, XL is the inductive reactance in ohms, and XC is the capacitive reactance in ohms.

5. Can I combine the impedances of individual components in a series RLC circuit?

Yes, the total impedance of a series RLC (resistor-inductor-capacitor) circuit can be calculated by adding the individual impedances. Ztotal = ZR + ZL + ZC, where ZR is the resistance, ZL is the inductive impedance, and ZC is the capacitive impedance.

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