What is Electrical Impedance?

Electrical impedance (represented by the symbol Z) is the measure of the opposition that a circuit presents to a current when a voltage is applied. In direct current (DC) circuits, resistance is the only opposition. However, in alternating current (AC) circuits, impedance includes both resistance (R) and reactance (X). Reactance is caused by components like inductors and capacitors.

Understanding the Formula

The total impedance in a series RLC circuit is calculated using the Pythagorean theorem because resistance and reactance are 90 degrees out of phase. The formula is:

Z = √(R² + (X_L - X_C)²)

Where:

• X_L (Inductive Reactance) = 2πfL
• X_C (Capacitive Reactance) = 1 / (2πfC)

How to Use This Calculator

1. Enter the Resistance value in Ohms (Ω).
2. Enter the Inductance value in millihenries (mH). The tool automatically converts this to Henries for the calculation.
3. Enter the Capacitance in microfarads (µF). This is converted to Farads during the process.
4. Enter the Frequency of the AC signal in Hertz (Hz).
5. Click "Calculate" to see the final impedance and the detailed steps taken to reach the answer.

Frequently Asked Questions

Why does frequency affect impedance?

In AC circuits, inductors and capacitors react differently depending on how fast the current changes. As frequency increases, inductive reactance increases while capacitive reactance decreases. This is why a circuit might behave differently at 50Hz versus 1000Hz.

What is the Phase Angle?

The phase angle represents the degree to which the voltage leads or lags the current. If the phase angle is positive, the circuit is more inductive. If it is negative, it is more capacitive.