How do Mosfets work and what are compatible?

[adengtg]

Ok, so just ordered the ASR112R2 GUARDIAN, its full metal and has EBB. it has a normal V2 gearbox and nothng special internals wise, other than blowback. i want to know what kind of mosfets are available for this and what they actually do. as far as i know, they just improve trigger response but can you jsut drop them into any gun or is there something else to it? 

Thanks for the help,

 

[Iceni]

An airsoft mosfet acts as a solid state relay. If you understand how a relay works then you know how a fet works.

The wires in essence go directly from the battery to the motor. And the fet breaks one of those wires. When a signal voltage is applied to the fet it allows the fet to open, this makes the gun shoot.

The advantage of the fet is the signal wire uses very low current to operate. This means because it's low current the mechanical contact points of the guns switch (trigger) do not spark (arc). The lack of this arcing means the contacts don't burn out.

You also have the advantage of the main gate part of the fet having a low resistance compared to the mechanical switch (trigger). This means more current to the motor, and 0 losses through the switch (trigger) as it is only providing a signal and not dealing with the total current drawn by the motor. Reduced resistance for the whole circuit mean better ROF and trigger response.


For an M4 build you are totally dependant on the available space in the stock. You will have no space over or at the side of the gearbox. With that in mind the best solutions for an m4 in my opinion would be a self soldered pico fet. It would require knowledge of how to solder, use heatshrink, and follow a wiring diagram.

The "gate PicoSSR 3 " is a good place to start with the searching about actual fet models. It's small enough to be wired into the buffer tube on an M4, but in order to do so you have to strip the gun and gearbox, make a new wiring loom, and solder it all in place. This means it's one of those jobs that is it best to pay someone to do for you if you have any apprehension at all.

 

[Hangtight]

Not quite true with M4s. With a little Dremel work you can fit a small Mosfet like the basic model from Sparklabs on the rear off the gearbox.

 

[Iceni]

Never thought about that position for a fet before.

It would save significant time if you changed shells to something like the upgraded lonex v2. Since it doesn't have the metal block section. A couple of holes and some small cable ties you could make a significant fet space  inside those shells.

 

[adengtg]

An airsoft mosfet acts as a solid state relay. If you understand how a relay works then you know how a fet works.

The wires in essence go directly from the battery to the motor. And the fet breaks one of those wires. When a signal voltage is applied to the fet it allows the fet to open, this makes the gun shoot.

The advantage of the fet is the signal wire uses very low current to operate. This means because it's low current the mechanical contact points of the guns switch (trigger) do not spark (arc). The lack of this arcing means the contacts don't burn out.

You also have the advantage of the main gate part of the fet having a low resistance compared to the mechanical switch (trigger). This means more current to the motor, and 0 losses through the switch (trigger) as it is only providing a signal and not dealing with the total current drawn by the motor. Reduced resistance for the whole circuit mean better ROF and trigger response.


For an M4 build you are totally dependant on the available space in the stock. You will have no space over or at the side of the gearbox. With that in mind the best solutions for an m4 in my opinion would be a self soldered pico fet. It would require knowledge of how to solder, use heatshrink, and follow a wiring diagram.

The "gate PicoSSR 3 " is a good place to start with the searching about actual fet models. It's small enough to be wired into the buffer tube on an M4, but in order to do so you have to strip the gun and gearbox, make a new wiring loom, and solder it all in place. This means it's one of those jobs that is it best to pay someone to do for you if you have any apprehension at all.

Oh yeah, i can solder it together. the gun im using has zero space in the stock but ive got a standard crane stock off an old gun. Thanks for the info mate!