What are electrical components in an airsoft gun?
The switch assembly is a component that is located inside the gearbox and has wires coming out of it going to other locations of your AEG. It is responsible for delivering an electrical current from your battery to the motor inside the airsoft gun. It functions as an on/off switch essentially, and is activated by the trigger. The standard configuration you will see is a switch assembly that will have a positive and negative lead to the motor and a positive and negative lead with a battery plug. There are more advanced configurations but we will go more into those later.
The switch itself is broken down into a few components. On the connector where your battery is hooked up, you will see two wires, a red (positive) and black (negative/ground) wire. The negative wire goes all the way to the negative terminal in the motor. The positive wire leads into one of the contacts in the switch. The other contact continues the circuit and goes to the positive terminal on the motor. This circuit is not connected by default. Instead you have a shuttle with another contact on it. This shuttle is moved back and forth by the pull of the trigger. The shuttle moves forward when the trigger is pulled and the contact on the shuttle completes the circuit between the two contacts on the switch and delivers power to the motor. A variation of this has one of the contacts leading to a terminal which touches the selector plate. This setup will have electricity having power pass through the selector plate contacts as an additional step before power comes through to the positive wire leading to the motor.
The switch assembly is a wear item and the contacts inside them will fail over time when they have built up carbon on them. The carbon comes from the arcing that occurs when the circuit is open and the shuttle is bridging the contacts. The electricity coming from the battery jumps the connection and creates a spark. The arcing makes your contacts dirty with carbon and degrades the efficiency in the switch, delivering less power than it should. You may notice this when even on a charged battery your gun is having a hard time cycling or has intermittent trigger response. This can also be exacerbated by using a high voltage battery and a lot of semi-auto fire. The semi-auto means you are making more arcing as opposed to full auto where you may shoot a couple shots but have it held down on one trigger pull. Unfortunately any maintenance or replacement of the contacts in the switch require full disassembly of the gearbox so consult an expert if you are trying to have this done. Typically switches are sold assembled so you have to make sure the configuration matches.
Some guns come equipped with MOSFETs and some tech savvy players may opt to add one into a gun. A MOSFET for airsoft use is a transistor used to modify the function of the switch in order to deliver current more efficiently to the motor. Some MOSFETs have added features but we'll talk about just the basics for now. Now the switch acts as the on/off signal but only uses a tiny bit of current to accomplish this. The switch no longer is responsible for delivering the entire battery current through the contacts and thus spares the contacts from a lot of wear and tear and arcing. The MOSFET delivers power straight from the battery to the motor when the gun is fired, making things more efficient.
Q & A:
Q: Should I get a MOSFET in my gun?
A: It depends on what you would like in your gun. Many MOSFETs now have fully programmable fire control units. This is a great upgrade to get on your gun. It does require good technical skills to install correctly. If you're not comfortable installing, we recommend having it professionally installed.
Q: Do I need to get an upgraded motor?
A: This depends on your goal. Upgraded motors can deliver extra torque as well as faster speeds. One of the biggest advantages is faster trigger response. Even if you're not going for a high speed build, the faster trigger response is a very good upgrade on your rifle.