What is Circuit Design

Circuit Designers try to make connections.

6. Putting it all Together

6.1. Electrical and Thermal Conductivity of Solder

Materials that conduct electricity well, often conduct heat well.  Of the common PCB materials, Copper offers the best compromise between price, conductivity, and manufacturability -- and it happens to be the second-best electrical and thermal conductor available to PCB manufacturers.  Copper has a greater conductivity than aluminum and even gold.

Thermal and Electrical Conductivity of Common PCB Elements.

This graph shows the relationship between thermal and electrical conductivity for common PCB metals.

Copper is used on PCBs to simultaneously conduct electricity and heat.