Hey I was playing with the serial monitor and installed a component backwards - reversing polarity.. the board's power light went dim and then went off and I heard the windows alert before I clued into what happened.. everything appears to be ok including the component. Is there any danger to my computer / usb port? I read that the uno has a themoresistor whos cutoff is 500mA plus I imagine the port itself has some hefty protection but I want to know if I should implement some kind of protection or just use a junk machine just for things like the monitor because the machine I'm using cost an arm and a leg.

Regards,
Mark

 

I have destroyed a couple of Unos and a Micro over the years through carelessness but I have not managed to damage a computer USB port yet. They must be well protected.My advice is to learn from your mistakes and always double check before you connect the power.

 

I read that the uno has a themoresistor whos cutoff is 500mA plus I imagine the port itself has some hefty protection

The USB spec calls for all ports to handle overcurrent situations. I recall reading in one of the earlier specs that a self resetting fuse was preferred.

 

One thing to avoid like the plague is connecting two power supplies that might have “ground” at different voltages. Current will flow and almost certainly destroy something.

Most of the time you can get away with connecting two supplies to establish a common ground, but the exceptions will stick in your memory forever.