The new technology of surface mounting provides opportunities and introduces more “Engineering Variables”. These “Variables” can be identified as the most critical concerns for successful surface mounting of transistors, integrated circuits, resistors, capacitors, etc. In short, the entire component complement used for a particular circuit design. These “Key” or critical parameters follow the design from the circuit concept by an engineer, through the process of fabrication; to the point of shipment. We will make several stops along this process journey and point out these critical areas.