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A couple of mosfet questions

Discussion in 'All Things Mod Making' started by HERBESTOS, Dec 3, 2017.

  1. HERBESTOS

    HERBESTOS New Member

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    Hi so i have made my 1st parallel unreg mosfet it went really well!

    So i want to make V2 in a g size box alluminium so due to less space and wanting to keep using the 14awg wire for the load bearing wires and have the slide switch inside the box as a main on/off. I have some questions.

    1) I read somewhere the back plate on the mosfet is also drain and the drain can go to that and the middle drain leg can even be cut. is this true and if so could that be mounted to the enclosure with solder so the body becomes the drain circut? this would save bending the wire back on itself to fix to the outer 510.

    2) I used 18awg for the switch and gate wiring but how thin can i go as this would save space? (i have 15K resistor on my mosfet)

    Cheers
    kev
     
  2. jock1092

    jock1092 Achiever

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    The back plate can be a drain tab and you can check with a multimeter of you don't have a spec sheet for it

    Depending on the enclosure you might need to prepare the surface if you want to solder to it and use it as part of the circuit.

    For switches you can use thin wire, thinnest I've used is 24g

    You can also buy a part called the switchfet on modmaker that is a tiny mosfet and switch in one, but you can also solder another standard switch to it instead of the tactile switch it comes with
     
  3. HERBESTOS

    HERBESTOS New Member

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    Thanks for the reply. It's answered those questions perfectly.
    I think it would make for a cleaner build In a smaller box like a Hammond g box.
    So could I cut the drain leg to the mosfet at the body without harming the mosfet leaving just the source and gate that would then be shrink wrapped once wired?

    Also sorry another question. I notice a lot of switches take place on the negative circuit. Is there a reason for this or can it be on the positive?

    Thanks
    Kev
     
  4. jock1092

    jock1092 Achiever

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    You can use a p-fet to switch on the positive but from what I know n-fets are usually higher rated and cheaper/smaller

    I would shrink wrap it but try to leave the tab and fix it so it's not shorting as that tab is also its heatsink, while it's fine to wrap it, if it can be left that's the better option
     

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