IR4905 P-Channel Power MOSFET

When you need to switch a lot of power, P channel MOSFETs are best for the job. These P-FETs can switch over 55V and 74A (with proper heat-sinking) and are TO-220 package so they fit nicely into any breadboard or perfboard. Heat sinking is easy with TO-220s, but because of the very low Rds(on) of down to 0.02 Ohms (depending on the Vgs - check the datasheet) you can get away with no heatsinking for pretty high loads! The threshhold voltage is up to 5V for 20A of current, so you can control it directly from a microcontroller running on 5V logic.