Surface mount resistors are also known as chip resistors usually with tiny black rectangles. The surface mount resistors have smaller edges on both ends and a glossy silver conductive edge. These surface mount resistors are located on top of the PCB where the surface mount resistors are soldered to the mating landing pads. Since these resistors are very small, they are usually placed in place by the robot and melted by solder and held in place.



SMD surface mount resistors are available in standard sizes. These SMD resistors are typically 0805 type ( 8mm long and 0.5mm wide ) and 0603 or 0402 ideal for large-scale board production. However, this type of surface mount resistor requires a stable, precise manual soldering method!
 
Surface mount resistors can be made up of a variety of materials. The most commonly developed surface mount resistors are made of carbon, metal or metal oxide films. In these surface mount resistors, the conductive metal film is wrapped in a spiral and covered with insulating material. This type of resistance production needs to meet certain standards. Resistors made from this resistance material will be made of carbon or metal film compositions.


In terms of the internal structure of some surface-mounted carbon film resistors, the resistance values from top to bottom are 27 Ω, 330 Ω and 3.3 M Ω. Inside the resistor, the carbon film wraps around the insulator. Carbon film resistors wrap precision resistance materials to mean higher resistance. This type of precision resistor may be wire-wound or made of ultra-thin metal foil. These resistors are usually more expensive than other resistors, as this type of resistor is a high-end resistor element and, due to its unique characteristics, is listed as a higher rated power or wider temperature range.


Surface mount resistors currently on the market are typically thick film resistor or thin film resistors, and thick film chip resistors are typically less expensive but less accurate than film chip resistors. In both resistor types, a small resistive metal alloy film is sandwiched between the ceramic substrate and the glass/epoxy coating and then attached to the terminal conductive edge.