overheating Circuit

[endowedbaron]

My MOSFET is heating very rapidly when connected to source. And the heat sink also overheats, now I want to add a DC motor to the circuit, the voltage source is 15v  but the DC motor is always 12v, now I am asking, how can I add the 12v DC fan to the circuit...

[kam]

what kind of circuit you use? what is the rated current of the motor?\

[Soldertraining]

The circuit is overheated mainly due to a loose connection. There may have other reasons also like an excessive current, poor connections, and insulation breakdown.

[JardCrocker]

Hi,...i am a new user here. As per my observation you are dropping 4V between input and output, and at 0.5A that makes 2W, and that is a LOT of heat without a heatsink.At 2W without any heatsink, the die of the device will be at a whopping 155?C if your ambient temperature is 25?C, and the case will be 10?C less, but 145?C is still a nice way to burn your fingers.

[kam]

YES!!! In one word. 2W in such a small surface can be very very hot