> perhaps a they meant a zener diode, which can be used to clamp a voltage? The downside being that it dissipates the excess energy across it's self. Maybe in

> perhaps a they meant a zener diode, which can be used to clamp a voltage? The downside being that it dissipates the excess energy across it's self. Maybe in conjunction with a self-reset polyfuse - buys just enough time to trip the fuse. > From the top of my flu-y head, connecting and disconnecting an inductive load (like a motor) can cause spikes. However in USB land, that's pretty rare. Exactly - and it's not all that rare. A USB fan, a spinning disk drive, etc. In the right condition even a capacitor can be a problem (difficult to simulate, but it can become a short-term battery cell).