A friend purchased a microcontroller-controlled lighting device and in the process of testing it, shorted the VCC and GND together for a second or two. Coincidental or not, the device stopped working thereafter, and he asked me if shorting the power could have been the cause.
It is my understanding that such a short could only really pose a threat to the battery or power supply (or the wire involved on the power supply side), given lack of current-limiting options or a fuse. The device should only experience power loss.
Can a power supply short cause a small circuit to permanently fail? If so, how?
I explained that the circuit might have failed because of the nature of the short: two wires making brief, intermittent contact. It might have created repeated instances of high inrush current which normally only happens once during power-on. Though, I doubt this theory because there shouldn't be much inrush current on subsequent power-on "events" as not enough time has elapsed for capacitors to discharge, etc.
Best Answer
A fast drop of DC input power can kill devices if they are not specifically designed to withstand this case. There are two main causes of damage: