When it comes to electronic assembly services, OBMFG does it all! In recent weeks, diodes and LED’s orientations have become quite a challenge. The standard in the past has been to put a line or a dot on one side of the part to indicate the Cathode side. This would be great if all diodes were marked on their Cathode side. Unfortunately, not all diodes themselves are marked on the cathode side. When OBMFG receives a drawing or CAD that has just a dot or a line, we have to do a lot of verification to make sure we are placing the parts accurately. Some parts have their anode marked and the mark on the board stays consistent with the Cathode. Other times, the engineer matches the mark on the part to the mark on the board so they both could be anode. Other LED’s have a mark on pin 2 or 3 – not the Anode or the Cathode.
With all the potential ways to interpret diodes these days, we thought it would be good to give some guidance in this component assembly process to help us make sure we place the part correctly. We recommend instead of a dot, dash, or line, you use the A for Anode or C for Cathode to mark orientation on the side that the part will be marked on to make the orientation clear. If the parts Anode is marked, put an A on that side of the part on the drawing and silkscreen. If the Cathode side is marked, put a C on that side of the part on the drawing and silk. If the part has more than 2 leads, we recommend matching the part mark to a mark on the silk/drawing and calling out at least 2 pin numbers per the data sheet.
We hope the following examples will help illustrate and clarify.
- See PG 8 for drawings. This one has Anode listed on pin 6.
- See PG 47. Anode marked on the bottom side, no top side mark.
- See PG 8. Anode marked as pin 1.
- See pg 1. Cathode marked.
At OBMFG, quality and accuracy are of the utmost importance. We want to be sure that you are satisfied with our service, expertise, and electronic assembly services. Flawless manufacturing quality and consistent on-time deliveries all at a competitive price – That’s the Out of the Box Manufacturing Difference!