# What Is Impedance Voltage:Facts,Problems,Examples

Impedance is the effective resistance of an electric circuit or an electric circuit component whose resistance changes with a different frequency of AC. Impedance can also be due to the combined effect of ohmic resistance and reactance. And impedance is represented by the letter ‘Z.’

## What is impedance voltage of the electrical circuit ?

Since impedance is a frequency-dependent resistance, then the relationship between voltage current and impedance can be defined by Ohm’s law as

V= I Z

Where V is the voltage drop across the impedance, I is current across the impedance, and Z is the impedance, although V=I Z is the scalar equation as we know impedance is a function of frequency, then it can also be defined as vw = iw x zw.

Impedance can be defined for any two-port passive network which can contain a resistor, capacitor, or inductor. When the network is condensed into one component, the voltage drop across that component is the impedance voltage.

The impedance of a resistor does not contain any imaginary part as the magnitude of the impedance is R, and the phase angle is zero for all frequencies. Where the impedance of a capacitor is frequency-dependent, capacitor impedance decreases with the increase in frequency. And the impedance of an inductor which is a coil, the impedance of an inductor is directly proportional to a frequency, which means the more extensive the frequency, the higher the impedance.

# How to Calculate Impedance Voltage ?

Impedance voltage can be calculated with the help of the equivalent impedance of the overall circuit.

If the impedance of the two-port network in a series has to be calculated, then the equivalent impedance of the series combination can be calculated as Z = Z1 + Z2 + Zn… where each component’s impedance is added together to get the equivalent impedance of the series connection.

If the impedance of the two-port network in parallel combination has to be calculated, then find the equivalent impedance of the parallel combination as 1/Zeq= 1/Z1+ 1/Z2….+1/Zn

The impedance of a circuit can be

Z = R for a circuit that contains only one resistor.

Z = Xc for the circuit which contains only the capacitor, and Xc is the impedance of the capacitor.

Z = Xl for the circuit which contains only the inductor, and Xl is the impedance of the inductor.

Inductive reactance Xl can be defined as X_L = i wL

Capacitance reactance Xc can be defined as X_C = 1/2 πL

The circuit which contains the register and capacitor in series Z2 = R2 + XL2

The circuit which contains resistor and inductor in series Z2 = R2 + XL2

The circuit which contains resistance capacitor and inductor in the series then Z2 = R2 + XL2

R in the AC circuit can be defined with respect to voltage asR = change in voltage/ change in current

After analyzing the overall circuit, add similar values of reactance with each other to get the total impedance of the circuit while calculating the total impedance considered the design of the circuitry such as if its component is in parallel or series combination with each other.

• For Calculating overall impedance where inductor and capacitor are in the series, then subtracting the magnitude of inductive reactance and capacitive reactance from each other.
• A two-terminal electrical circuit network impedance can be a complex quantity so that the impedance can be represented with phase and magnitude characteristics.
• After calculating the overall impedance of a circuit with the help of Ohm’s law, the voltage drop across impedance can be calculated with known current through the impedance.
• A two-terminal electrical circuit network impedance can be a complex quantity so that the impedance can be represented with phase and magnitude characteristics.

V= I Z

# How to Calculate Impedance from Voltage and Current ?

The impedance of a two-port network can be calculated with different parameter representations.

According to Z- parameter or open circuit impedance parameters, the input, and output voltage of any two-port network can be represented as V1 and V2 that can be expressed in terms of input and output currents I1 and I2.

[V] = [Z] [I]

Where [Z] is the impedance matrix.

In this method, the overall two-port network is represented with a rectangular box and the direction of currents and voltage from each input or output port of the network.

Getting equation from the matrix:

V1 = Z11 + I1 + Z12 + I2

V2 = Z21 + I1 + Z22 + I2

Now assume the output of two-port to be open-circuited open circuited, so I2 = 0

So now Z12 = V1/I1

Now, assume the input of two-port to be open-circuited open circuited, I1 = 0

And, now Z22 = V22.I2

Z11, Z12, Z22, Z21 are also called impedance parameters or open circuit parameters of the two-port network.