# Formula Ohm's law Voltage Electrical resistance Electric current

## Voltage

`\( U \)`Unit

`\( \mathrm{V} \)`

In order for an electric current \(I\) to flow between two points on the conductor, positive and negative charges must be separated, that is there must be a voltage between these points. The mutual attraction of the opposite charges creates an electric current.

## Electrical resistance

`\( R \)`Unit

`\( \mathrm{\Omega} \)`

The Ohm's law is characterized by the fact that the resistance \(R\) is constant! So it doesn't matter what voltage is applied, the current through the conductor will adjust so that the ratio \(U/I\), that is the resistance, always remains constant.

At a current of \(I = 0.1 \, \text{A} \) and a voltage of \( U = 10 \, \text{V}\), the resistance is \( R = 100 \, \Omega \).

## Electric current

`\( I \)`Unit

`\( \mathrm{A} \)`

At a current of \(1 \, \text{A}\) (1 amp), \(1 \, \text{C}\) (1 coulomb) of charge flows through the conductor per second.

With a resistance of \(R = 10 \, \Omega \) and a voltage of \( U = 1 \, \text{V}\), a current of \( I = 0.1 \, \text{A} \) flows.