I set up the basic circuit above as a way to test various LEDs and transistors with a 555 timer circuit in place of the switch. However, when I put an IRFP460 transistor there, even when the switch was open the LED remained lit. To say it in another way, there was no voltage going to the gate on the mosfet, yet I'm clearly getting current between the drain and the source. I'm pretty new to this, so what I'm wondering is what aspect of the specifications of the transistor allows this current flow to happen. Thanks in advance!