MOSFET help

[magnum]

I recently bought a big box of random parts from a guy, and I found this MOSFET. It had 3 wires, all of which are pictured. The smallest one, just sort of fell out when I picked it up. Is third, smaller wire vital to the function of the MOSFET? Can I just plug it in and play, or do I need to hardwire it? I have no issues with electrical stuff, I'm just still a little new to MOSFETs in the world of airsoft.

[Shadow (314)]

Yes, you need that wire. All three are necessary for it to function. Did you see the solder point where it was connected? You could try to just re solder it back on and test it.

[X]

Looks like your MOSFET should be wired like the first picture in this link...

www.airsoftwarriors.co.uk/forum__10/re-mosfet-for-a-p90.html

The wire that comes from the MOSFET which is also connected to the motor should be the thicker wire. The thin wire should not have any connection to the motor.

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[magnum]

I can try and peel back the wrap on the FET and see if I find it's original connection point. So what is the purpose of that third wire? Sorry, I'm still a little confused.

[X]

A traditional gearbox sends all of the current through the trigger contacts causing electrical arcing which damages the contacts over time. A MOSFET uses a signal wire (low current) attached to the trigger contacts to switch on the power internally. Since a MOSFET uses solid state switching there is no degradation of any contacts because technically it doesn't have any.

Edit: disregard what was here. That's how my MOSFET works. Yours is a little different.

Your MOSFET uses the signal wire to sense when your trigger is closed. When that happens it closes the circuit to your motor causing your gun to fire. So on a timeline (think micro seconds)... You close the trigger, electricity flows to the MOSFET from the battery through the third wire, then this electricity through the magic of electronics connects the other two contacts on the MOSFET together. Thus completing the circuit which powers your motor.

On this link yours is the second one down. Mine is the bottom one.
m221.photobucket.com/albumview/albums/kahuna_92/mosfet/MOSFET-WiringDiagram.jpg.html?o=1


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[magnum]

This will be interesting, because the project gun I was going to stick it in is front wired. So does a MOSFET eliminate the need for a fuse?

[X]

A simple MOSFET does not act as a fuse. Some advanced MOSFETs do have built in thermal fuses but I'm not sure what you have.

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