15 August, 2014
New gadget measures negative resistance
The device fully satisfied my curiosity. Actually one surprising result was that the charger for my Samsung Galaxy Note 8 has a negative output resistance.
I measured other chargers also, without finding a negative output resistance, so it seems as if it applies to this particular charger only. Out of curiosity, I also measured the current consumption of my Arduino Mega to 0.08 A without any shields connects.
The unit has two outputs which are different from each other. Output 1 is a fully functional USB port, while output 2 only connects DC power. What is that good for? Well, the epanoroma blog opened my eyes to the utility of this. If you charge your phone at some public place, then this feature isolates the data port of your phone. That may protect you from being hacked.
So there you see. The €5.13 were well spent and I even learnt something new by giving in to the temptation to click "Buy It Now" on Ebay.
But why does the Samsung charger have what amounts to a negative output resistance, is it by design or by accident?