MOSFET unit features

On this page all the different features of MOSFET units are listed. Some features are offered in all of our units, while others are only offered in our advanced unit, the microSMART. Check the video below to see some of the features in action.

Basic features

Improved response time

All of our MOSFET units improve the response time and rate of fire. Because the mechanical switch in the rifle is bypassed, the resistance between the battery in the motor is lowered, and the motor can turn faster.

Thermal protection

All our units have some type of thermal protection. In simple units, a thermal fuse is installed, which turns off the unit when temperature exceeds about 120 degrees Celsius. When the unit cools down, the unit is turned back on again. Advanced units have temperature monitoring sensors and they can warn the user when there is an over-temperature condition.

Stand-by current draw

In all units the stand-by current draw is minimized as much as possible. In the basic microFET unit the current draw is zero, because the unit is only turned on when you press the trigger. Other units have to powered from the battery to work. In both the microAB and microSMART the current draw is roughly the same, about 0.2 mA – discharging a 1500 mAh battery from 100% to 90% charge in about one month.

Advanced features

Active braking

Some units offer active braking, which means that the motor is brought to a stop after the shot is completed. This means that the piston will remain in the front-most position after a shot and the spring will be in the released position. Powerful active braking CAN increase motor wear and heat, so we recommend powerful braking only on DMR rifles and rifles, where you shoot on semi-auto most of the time. The microSMART unit offers adjustable breaking, which, on lower strength, can be safely used on full-auto rifles as well.


Precocking is a feature in which, after a shot, the motor keeps spinning for a fraction of a second and precocks the piston near the rear position, so the next shot is near instantaneous. In this precocked position the nozzle is already sealed against the bucking and the BB is stationary in the hop-up chamber. This mimics closed-bolt operation and can increase rifle accuracy.

Semi delay

This is a feature where after a shot the next shot is disabled for some time, preventing the user from shooting the gun too fast on semi-auto. This is usually used in DMR rifles to limit the rate of fire to 1 BB per second. The microSMART unit offers adjustable semi delay to offer even more flexibility.

Semi only mode

This mode can limit a DMR rifle to semi-only operation without modifying the gearbox or other parts. The rifle will shot single semi shots on both (semi and auto) selector positions.

Over current protection

The microSMART unit measures current draw through the motor during a cycle and can detect over-current conditions, acting like a fuse in a rifle. The over-current limit is pushed quite high because some AEG set-ups have very high starting currents. When the current rises above ~300 amps, the microSMART will turn off the motor and turn itself off.

Battery monitoring

MicroSMART measures battery voltage upon power-up and also just after a shot. From this voltage the state-of-charge is calculated and if the battery charge falls below 20%, the unit will warn the user. Different battery technologies can be adjusted to cover all different options.

Adjustable rate of fire

The microSMART unit can lower the rifle’s rate-of-fire if desired. This is done with PWM – quickly cycling the power to the motor on and off. To retain maximum response time, the first shot is always done at full power. In effect, the lowered rate of fire is noticed only in burst and full-auto fire modes.

Burst to auto hybrid mode

In this mode, the rifle will transition automatically from burst to full-auto, if the trigger is held for some time after the burst cycle has completed. The time between burst and full-auto can be adjusted in the microSMART unit.