topic Re: SMD LED not indicated +/- on PCB in Fusion Electronics Forum

SMD LED not indicated +/- on PCB

CaptainMJ — Thu, 07 May 2020 09:01:34 GMT

Hi All,

Perhaps a simple question, I recently sent off my first PCB to manufacturing and they came back asking for positive and negative orientation for the SMD LEDs as well as an SMD Diode. After some review i notice that the orientation is not indicated on the board in any way. My question is what is the norm here. Browsing some of the LEDs in the library files many or most doesn't seem to print orientation on the board. If someone here can share best practice for how to do this correctly that would be very much appreciated. Note that this problem seem to be unique to the SMD components.

Many thanks,
Marcus

Re: SMD LED not indicated +/- on PCB

RichardHammerl — Tue, 12 May 2020 10:40:38 GMT

Hi @CaptainMJ

the silkscreen usually shows a line (the cathode band) that indicated where cathode is located.

And it's similar with LED:

Hope this helps.

Re: SMD LED not indicated +/- on PCB

CaptainMJ — Mon, 01 Jun 2020 13:37:42 GMT

Hi Richard,

Many thanks for all the help. I think the issue is specific to a few the components I used. It does have very weak marking. To make it easier for the PCB production company i then wanted to add a line to the footprint, but it seems when I save the footprint it just creates a new file somewhere in the project and it doesnt seem to be linked to the component, I haven't found a way to do that. It saves my new footprint successfully but when i click the component on my PCB again it still has the old footprint. I don't want to create an all new component,. I just want to edit the existing footprint, if possible.