Why Heat Sink in MOSFET connected to a wire?


Joined Mar 30, 2015
With the lack of context you've given us, it's unlikely anyone will be able to give a definitive answer.

As shown, the circuit is worthless because 2 of the three terminals on the MOSFET aren't connected. If they were connected, one of the 3 terminals would be connected to the tab. The wire attached to the heatsink could be making an electrical connection to the tab.

It seems to me that a screw would be a more appropriate fastener than a nail.