MOSFET

Stock AEG trigger contacts carry the motor's full current directly, which pits and burns them over time and eventually causes weak, inconsistent shots. A MOSFET moves that current load onto a transistor switched by a small signal current, so the trigger contacts only ever handle a fraction of the amperage.

Beyond protecting contacts, most MOSFETs add active braking (stopping the piston at the same point every cycle for FPS consistency), burst-fire modes and low-battery cutoff. Programmable versions let a tech set exact burst counts or trigger debounce, which is why a MOSFET is one of the most common single upgrades on an otherwise stock AEG.

Installing one is also the point where most technicians upgrade to thicker gauge wiring at the same time, since a MOSFET's benefits are limited if the rest of the circuit is still the thin factory wire it was designed to protect.