Author
Home > Technology > What is the Difference Between Impedance and Resistance?

Guilherme Mazui

•3 minutes to read

What is the Difference Between Impedance and Resistance?

🆚 Go to Comparative Table 🆚

The main difference between impedance and resistance is that resistance opposes the flow of both direct current (DC) and alternating current (AC), while impedance solely opposes the flow of AC. Here are some key differences between impedance and resistance:

  • Application: Resistance is used in both DC and AC circuits, while impedance is used only in AC circuits.
  • Nature of opposition: Resistance opposes the flow of current due to electrons in a conductor colliding with the ionic lattice of the conductor. Impedance, on the other hand, is the opposition present in the flow of AC and is created due to resistive elements and reactance.
  • Composition: Impedance consists of two parts: resistance and reactance. Reactance is the resistance offered to AC current by inductors and capacitors.
  • Frequency dependence: Resistance does not vary depending on the frequency of the current, while impedance varies with the frequency of the AC current.
  • Representation: Resistance is represented by the letter "R" and is expressed using real numbers, such as 5.3 ohms. Impedance is represented by the letter "Z" and is expressed using both real and imaginary values, such as R + ik.

In summary, resistance is the opposition to the flow of electric current, regardless of whether it's DC or AC, while impedance is the opposition to the flow of AC electricity, which is influenced by both resistance and reactance.

On this page
  • What is the Difference Between Impedance and Resistance?
  • Comparative Table: Impedance vs Resistance

    • Comparative Table: Impedance vs Resistance

    Here is a table comparing the differences between impedance and resistance:

    Feature Impedance (Z) Resistance (R)
    Definition Impedance is defined as the opposition present in the flow of alternating current. Resistance is defined as the opposition present in the flow of both direct and alternating current.
    Types of circuits Used in AC circuits only. Used in DC circuits and AC circuits.
    Caused by Occurs due to resistive materials and reactance (inductance and capacitance). Caused solely by resistive elements.
    Representation Represented by the letter 'Z' and can be complex (real and imaginary values). Represented by the letter 'R' and is always real.
    Magnitude $$ZL = 2\pi fL$$ for inductance, and $$ZC = \frac{1}{2\pi fC}$$ for capacitance. Does not vary with frequency of direct current.
    Phase Varies with frequency. Remains constant.

    Please note that the table is mostly based on the information provided in the search results.

    Read more:

    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.