Speeduino

I have a few of these that I find quite useful:

https://www.banggood.com/DC-Power-Male- ... rehouse=CN

Sometimes its easier to use a wallwart than a bench power supply.

The power jack is almost never used with speeduino

No. The adapter is just a simple way of connecting a Speeduino or whatever to a Walwart, most people will have a 12v wart lying around somewhere. If you were using the Power jack on the Arduino then you wouldn't need an adapter.

Just to be sure any readers are not confused; you can not power Speeduino through the Arduino Mega power jack with 12V. Power is to the Speeduino PCB 12V connection points only. The linked connector is only for testing, in order to make 12V connection to the Speeduino PCB easier. I use a similar connector with a laptop power supply adapter or cordless drill battery.

David