I have a simple question I think... I have a very simple test circuit using a 6v battery, light bulb and a MOSFET(IFRP06N4). I am just testing the MOSFET as a switch turning the light on and off. When I charge the gate by touching a wire between the source and gate the light comes on thats great. I can switch the light off by touching the drain and gate which is good also. Basically things work as I would expect... However, my question is this. When I turn the light on and measure the voltage I am only getting about 3V across the source and drain. I was expecting something closer to 6V? The reason I am asking is that if I take my battery and hook it to the bulb directly it is about twice as bright as with the MOSFET in the circuit. I thought a MOSFET acted basically as a switch so seeing the voltage drop basically in half does not seem right? Am I doing something wrong?