How to wire ULN2803 | darlington pair ULN2803A wiring

The darlington pair family of ULN like the ULN2801A ULN2802A ULN2803A and ULN2804A are pretty common but a bit different in wiring. While it is in itself simple, it's a bit counterintuitive how to wire the ULN2803A.
In case you wanna connect loads to your GPIO pis of your Raspberry Pi, ESP32 or Arduino, a darlington pair is a good choice to protect your GPIOs!
So check out this video where we check out the schematic and a little experiment to see how it works.
But before you dive into this video, make sure to watch the darlington pair basic video for a fundamental understanding of a darlington pair:
• What is a Darlington p...

[@chrisheaps9893]

With the IC sinking up to 8 connections (relays/ transistors/ other) does it need a heatsink?

[@blueprintiot]

Not really. Obviously depending on your use case, I normally use it to switch a relay as in the cybergarden part 4 episode. If you know the current you're planning to switch and check the resistance in the datasheet you can quickly calculate the heating power.... What would be your usecase?