Hello everyone! I am building a small heating project -- think of it like a crockpot. I have nichrome wire wrapped around a ceramic vessel to hold liquid at a specific temperature. The crockpot uses about 3 amps at 12 volts and can boil 4 oz of water in about 30 minutes.
Anyway the trouble I am having is I want to use a transistor to turn the heater on an off. I know a relay might be better but I was hoping to keep everything solid state. I am using this transistor:http://www.adafruit.com/datasheets/irlb8721pbf.pdf
The problem I am having is with using the gate pin on the transistor to actually turn off the heat. With the heater circuit wired up thru the transistor everything works fine and the transistor even stays pretty cool to the touch while heating the water. If I touch the gate pin to the 12V+ rail, it turns off the way I want to. If I try to drive the gate pin from the 5V on the arduino however, nothing happens. The heat stays on.
12V is coming from an old laptop power supply I had sitting around while the arduino is being powered off my USB port.