How to Install a MOSFET Airsoft

The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is often misunderstood, but the best airsoft guns have them installed. The MOSFET is the brain of your AEG and allows you to control the rate of fire, or ROF, by allowing you to fire the gun in full auto. (This article steps you through how to install a MOSFET Airsoft.) This is important for two reasons: The first is that the MOSFET protects the trigger contacts from burning up with each shot. In the event of a short or a weak battery, or an improperly charged battery, the gun will automatically stop firing. The second is that the MOSFET is a mechanical switch that prevents double-fires and the situations that cause them.

Convinced yet 🙂 ?

So, how do I install a MOSFET airsoft? A MOSFET is installed in an airsoft gun by removing the gearbox, detaching wires from and reattaching MOSFET wires to the trigger contact using a soldering iron. Next you attach the correct wires to the motor connector and Deans connector.

To read more step by step instructions on how to install a MOSFET in your airsoft gun, continue down below!

How to choose a MOSFET (4 Types)

Before you purchase your MOSFET you need to see which type of MOSFET will suit your needs best. Below are the different types of MOSFET you should consider:

1. Regular MOSFET

Regular MOSFET are the simplest type of MOSFET which functions to divert the current from and protect your trigger. These will be the cheapest form of MOSFET so a great place for a novice to try your hand at altering your airsoft gun.

2. Plug and Play

Most versions of plug and play MOSFETs are just that, you plug in the MOSFET between the AEG and the battery to redirect the current from the trigger and you are set to play. This will not require you to do any rewiring. Some plug and play will need to be rewired if they come with any extra features.

3. Programmable

Programmable MOSFETs allow for you to give more customization to your airsoft gun. You can change how the currents are diverted in the circuit and to allow for more functionality of your airsoft gun. Installing a programmable MOSFET will require soldering and rewiring.

4. Drop-in trigger boards

Drop-in trigger boards will be the most expensive, but also the most desirable MOSFET. These MOSFETs can improve the feel of your airsoft gun’s trigger, add on bluetooth capabilities, replace trigger contacts with sensors, etc. You will also need to use soldering and rewiring to install a drop-in trigger board.

What you will need to install your MOSFET

• Soldering iron
• Solder 
• MOSFET unit
• Wires
• Wire clippers
• Wire strippers
• Heat shrinking 
• Pliers 
• Any other tools needed to disassemble your airsoft gun.

Step 1- Review instructions provided in MOSFET kit

It is important that you check the instructions that were provided with your MOSFET and alter any of the following instructions so that they align with the steps given by the manufacturer. 

Step 2 – Disassemble your airsoft gun

Be sure to take note of what you are removing from where. It may be best to take pictures of the process so that you know what screws go back where when reassembling your airsoft gun. If you are unsure of the disassembly process for your specific airsoft gun, look online for guides regarding specific parts of your model.

Step 3 – Remove the gearbox

Remove the gearbox and disconnect the wires attached to the trigger contact by soldering them off. Check online for your specific model for how to remove and identify the gearbox.

Step 4 – Trim wires

Trim the wires that come with your MOSFET kit to your desired length based on your airsoft gun. Use wire strippers to strip the insulation from the ends of the wire. Tin the ends of the wire with solder.

Step 5 – Solder wires to trigger contacts

Use soldering iron to install the thin tinned wires to the unattached trigger contacts. Do not allow positive wires to touch to avoid shorting out your MOSFET. 

Step 6 – Solder wires to motor connector

Take the tinned motor connectors and attach them to the wire connectors using the soldering iron. Using a lighter install heat shrink on the wires. This is important to not short out your MOSFET.

Step 7 – Solder wires to Deans connector

Take tinned motor connectors and attach them to the wire connectors using the soldering iron. Install heat shrink on the wires using a lighter. Take the Deans connector and use the soldering iron to tin it. Take the wires and connect the positive wire to the positive wire on the Deans connector and negative to the negative on the Deans connector. Make sure you match positive with positive and negative with negative.

Step 8  – Check placement of wires

Once you have finished soldering, ensure that the wires are fitting correctly in their placements. Make sure the safety bar and trigger can move over the wires and that the signal and positive wires are pushed down as far as possible where the motor shaft comes up. Ensure the gearbox can also attach without any wires in the way.

Step 9 – Check for correct installation

Reattach the gearbox and check to make sure the trigger and safety works correctly.

Step 10 – Finish reassembly

Once you have confirmed that the MOSFET is functioning and installed correctly, finish reassembling your airsoft gun.