Component Identification can be confusing, especially when it comes to sourcing parts made by different manufacturers. One company may have a completely different part number for an identical product from a different manufacturer. There are some details that can help you determine specific values of components simply based on their shape. Here are three examples of the same component. 2 are made by the same manufacturer one is not. They all have different voltage ratings. You can tell this by the shape of the heat-sink, the little metal part sticking up off of the back of the component. If you're still confuse, bring your wiring diagram, schematic or parts list with you and we'll help you find the appropriate part or a direct substitute for it.