# The simple exactly definition of impedance of PCB board

**Top 3 topic of impedance cotrol PCB**

## Why we discuss Impedance of PCB board?

Even though the definition of **impedance of PCB board** can be searched on Google.

There were many green hands don’t know what is the impedance of PCB board.

Most of the introduce use complex mathematical formulae and some terminology words to describe.

Those articles, make most PCB designer confused.

Then is the most important for the PCB design process.

In most complex PCB board, 4MCPCB experts suggest considering the impedance factor.

Even some experienced engineers also have reference some design books.

## The aim to introduce impedance of PCB board

As a professional PCB manufacturer, we also know the more technology terminology can be better.

But Emma wants to let more PCB guy learn this definition.

So we will strip back the terms and pare down the formulas.

## The simple exactly definition of impedance of DC circuit application

Our 4MCPCB experts told Emma that separately discuss this definition is more professional, DC circuit and AC circuit area.

In DC circuits, most of the time the current flow is steady.

There is of the type of opposition to this flow which Resistance.

This opposition flow is named impedance.

AC circuit impedance is measured in ohms (Ω).

## The simple exactly definition of impedance of AC circuit application

Similar in the AC circuit area, it also can experience another form of opposition to the current flow, Reactance.

The reluctance is different with resistance, even the AC circuit area also have resistance form impedance.

In AC circuits area, the combination of these two forms of opposition to current flow that called impedance.

In some electronics PCB books, the impedance is signified by the symbol Z.

From this definition, we can know that the impedance is acquired resistance and reactance value.

That’s the reason why in some experience PCB designers can know impedance very quickly.