PCB Libraries Forum : Pin1 Cathode https://www.PCBLibraries.com/forum/ Sun, 05 Apr 2026 08:26:08 +0000 Tue, 26 Jul 2022 12:49:13 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=3148 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Pin1 Cathode : Pin 1 for Cathode was started...]]> https://www.PCBLibraries.com/forum/pin1-cathode_topic3148_post12519.html#12519 Author: Tom H
Subject: 3148
Posted: 26 Jul 2022 at 12:49pm

Pin 1 for Cathode was started back in the 1990's with OrCAD Layout (which was taken offline in 2007 after Cadence bought it). 

I created the CADPRO library and sold a copy to OrCAD as their default library before Cadence acquisitioned them. 

All the diodes had pin 1 as the Cathode so OrCAD Capture symbols put pin 1 on the Cathode. 

It is a DeFacto standard because OrCAD Capture was the number one most used schematic tool for many years. 

We now use C and A for the pin assignments to avoid mistakes and confusion. 

]]> Tue, 26 Jul 2022 12:49:13 +0000 https://www.PCBLibraries.com/forum/pin1-cathode_topic3148_post12519.html#12519 <![CDATA[Pin1 Cathode : Is there a specification that...]]> https://www.PCBLibraries.com/forum/pin1-cathode_topic3148_post12518.html#12518 Author: ArtGon007
Subject: 3148
Posted: 26 Jul 2022 at 10:31am

Is there a specification that specifies pin 1 is cathode for diodes? Or is it just industry standard?Diode issues strike again...]]> Tue, 26 Jul 2022 10:31:02 +0000 https://www.PCBLibraries.com/forum/pin1-cathode_topic3148_post12518.html#12518