Conducting Material
![](https://www.electriquel.com/wp-content/uploads/2021/05/carbon-1.png)
Electrical Carbon Properties
![](https://www.electriquel.com/wp-content/uploads/2021/05/motor.gif)
- This material is made from graphite and other form of carbon.
- Conductivity of Carbon is less than Copper (Cu) and Aluminum (Al) but its surface is smoother so it is used to make brushes in a Electrical Machine.
- Carbon brushes are graphited or heat treated to increase conductivity and reduce hardness.
- Graphite has negative temperature coefficient
R=Ro(1-αΔT) as Temperature increases Resistance decreases
Brush drop Voltage (VBD=IR=Constant)