The difference between impedance and resistance

The difference between impedance and resistance is that impedance is a vector sum, including resistance, inductance and capacitance; resistance is pure resistance and is not affected by frequency. In applications, impedance is used for impedance matching, resonant circuits and sensing, while resistor is used for power calculations.

The difference between impedance and resistance

Impedance and resistance are two key concepts in electricity. Although these two The terms are often confused, but there is a clear distinction between them.

Impedance

Impedance is the total resistance to the flow of current in a circuit. It is the vector sum of resistance, inductance and capacitance. Impedance is expressed as a complex number, having magnitude and phase angle. Magnitude represents the total resistance of the circuit, while phase angle represents the phase difference between current and voltage.

Resistance

Resistance is the pure resistance to the flow of current in a circuit. It is a scalar quantity that indicates how easily a material blocks the flow of electricity. Resistance is expressed in ohms (Ω), and Ohm's law defines resistance as the ratio of voltage to current.

Difference

The main difference between impedance and resistance is:

• Property: Impedance is a complex number , while resistance is a scalar quantity.
• Components: Impedance consists of resistance, inductance and capacitance, while resistance consists only of resistance.
• Frequency Dependence: Impedance changes with frequency, while resistance is generally not affected by frequency (only under certain circumstances).
• Phase Difference: Impedance can introduce a phase difference between current and voltage, while resistance does not introduce a phase difference.

Application

Impedance and resistance are widely used in electricity:

• Impedance matching:In transmission lines, impedance matching is key to ensuring maximum power transmission and preventing reflections.
• Resonant circuit: Impedance plays a vital role in the resonant circuit, determining the resonant frequency and quality factor of the circuit.
• Power Calculation: Resistors are used to calculate power dissipation in a circuit.
• Sensing: Impedance changes can be used to sense various physical quantities such as temperature, pressure, and position.

The above is the detailed content of The difference between impedance and resistance. For more information, please follow other related articles on the PHP Chinese website!