Double taps mosfet

[Dannn]

I've just got lots of components to make one of the double tap mosfets anyone made and used one ?

[Dannn]

One none breaking mosfet made !

[ImTriggerHappy]

How long did it take?

[Sitting Duck]

You got a link to this "double tap" MOSFET ???

 

Tbh it looks like a normal 3034 one without a TVS diode

Which many use even though a 3034 has some basic protection.

 

By the way you should use the tab for negative motor wire

Keeps voltage well away from 2 outside wires plus the tabe handles much more current

 

Think it's Rusty's guide or something I based my stuff on

But same meat different gravy

 

£2 to £2.50 per fet cost if you buy say 10 or more

Just make sure you get GENUINE ones

The snides from fleabay just melt

[Sitting Duck]

What is underneath basic fet ???

 

And F U C K ME

 

them 2 neg wires are close hence tab

Middle n right legs jeez lots of shrink on them

 

Curious as to the underneath bit thingy

Coz looks thick something or a flat TVS diode??

 

Soz for commenting, my soldering ain't perfect

I use chunky TVS coz in stubby stocks I got plenty room

Stock tube might be different

[ImTriggerHappy]

£19 Gate nano asr mosfet at firesupport.

Will replace for free if it ever fails.

No hassle better made doesn't break the bank.

But 10/10 for having a go yourself.

[Sitting Duck]

Firestorm fet £10 with thermal fuse delivered

 

Baby mofo fet if you don't wanna make your own

99.9% fet's blow from bad fitting

 

The decent ones I mean

Cheap snides fail no matter who fits them

[Lozart]

And F U C K ME

 

them 2 neg wires are close hence tab

Middle n right legs jeez lots of shrink on them

 

 

My thoughts exactly.

 

Although to be fair I also thought "nice soldering" the joints themselves are actually quite tidy!

[straffham]

Nice job Dannn, interested to know how it performs.

[Dannn]

It took literally 10 mins to make, I put heat shrink over each joint then heat shrink over the whole thing.

Seems to work as the gun works !

It cost about £4 and av half hour in total to do.

All the parts were from RS components so all decent bits.

[Sitting Duck]

RS are cheap for 3034's if you buy 10 they are like £1:52 or something...

 

http://uk.rs-online.com/web/p/mosfet-transistors/6887204/?searchTerm=IRLB3034PBF&relevancy-data=636F3D3226696E3D4931384E4B6E6F776E41734D504E266C753D656E266D6D3D6D61746368616C6C7061727469616C26706D3D5E5B5C707B4C7D5C707B4E647D2D2C2F255C2E5D2B2426706F3D313326736E3D592673743D4D414E5F504152545F4E554D4245522677633D424F5448267573743D49524C423330333450424626&sra=p

Is where I bought mine from
Cheaper than farnell and free ship on £30 or something like that

Get some wire n some other bits, maybe get a m8 to go halves with ya etc....

People think it's a lot of messing about, best thing is make a few at a time once you got iron up to temp.
Not much effort really, besides you gotta do same amount of soldering n care when fitting a pre-made mosfet

[Sitting Duck]

linky for the way I do it:

 

http://ncairsoft.org/forum/showthread.php?7516-Rusty65-s-MOSFET-building-guide

 

and also same stuff here:

 

http://unconventional-airsoft.com/2009/08/26/how-to-make-a-basic-mosfet-switch/

 

diode is a pain but they use one - so who am I to argue

if you are making one - make a few....

 

for what it is worth - the #6 bolts equate to our M3.5 bolts

yes M3.5 - M4 is a bit too big to go through fet eyelet and M3 is a bit thin

M3.5 is the bolts used is electric socket/switches in ya house but you need a m3.5 nut spring washer

 

That is the usual basic fet gospel, some use other mosfet's but the 3034 is said to be one of the best ones available

 

well that is the way I do it....

 

only minor difference toi Rusty65 is that I wrap the resistor across fet - leave resistor wire excess for now...

position the diode leg the right leg where it goes - then wrap the excess around diode leg to hold in place & solder

same for signal wire resistor - fitted by wrapping the excess around it & solder

just a bit extra help holding it all together when soldering them to fet legs

 

get the bits ready & shaped - wrapped together - ttsszz ttsszz - fet done

repeat for other 2 or 3 fets - sorted

[Dannn]

What's the diode for ?

[Sitting Duck]

it is to prevent any back surge of current or something so the fet bible says.....

 

I got an alternative spec tvs diode coz could not locate exact model

but similar spec bollox - makes it a bit bulky but like I say I often use stubby fixed stocks for good size cheap block batteries in M4's

 

v2 will need box opening to install wiring for fet

 

v3 can be fitted without needing to open up gearbox like in V2's

 

major decision is how thick the wire you can use and where to locate the fet itself

on its own the fet does jack $hit except protect the contacts on heavier juice

 

it is an additional device to switch on so in reality I guess it adds a few nano seconds in a normal stock gun

it does not imho give you faster trigger response or make you more attractive to women etc.....

 

it is when you rewire with thicker wire + deans that the fet comes into its own and it is the other bits that give the faster response

not the mosfet - the fet just allows us to safely switch higher juice for heavier loads on juicy motors etc....

 

That is where the trigger response comes from - not the fet itself

the fet just manages the bigger juice safely keeping your contacts looking good rather than deep fried

[Sitting Duck]

I'm no expert - far from it

well even further from it when you see how the real techy pro's can fit these basic 3034's inside their gearboxes:

 

 

yes I am but a humble trainee apprentice noob

 

actually still think fitting inside a box is not a very wise option

if I wanna change out a basic to AB fet or even a prgrammable one at least I don't have to open gearbox up

but maybe for some compact guns - even AEP's people have managed to squeeze in a fet in the tighest of places

 

clever mofo's out there - G&G fet dept should take note

[Dannn]

All this info is great!

I'm gonna girder a few capacitors too, I think I'll be able to fit them in somewhere !

[Sitting Duck]

Capacitors ????

 

nah that is old skool way of boosting ya charge on crappy nimah's

really don't think anybody still does that - they just fit bigger and higher burst lipo's

(some yanks go nutz on 14.8v - jjeeeezzz how fast ya need to go chaps)

 

if ya got lipo you got plenty of mojo

 

a lot of these guides are old but the fet malarky is still in use

often many still use 3034 as best airsoft fet

 

the capacitors - like for holding charge is obselete with lipo's now being the norm

they can unleash juice quicker tha you can rip open a carton of Del Monte or Ocean Spray

[Dannn]

Ahhhhh I've got 50c 11.1 lipos.. No capacitor needed then haha

[Sitting Duck]

me thinks not - go for 60c instead - jeeeez

I'm content with 25 to 35c performance atm

plus sticking to 7.4v and squeeze out every last drop

(without the pips or pulp)

[ImTriggerHappy]

Ahhhhh I've got 50c 11.1 lipos.. No capacitor needed then haha

No but plenty of spare parts for your gearbox is probably a necessity.

[Dannn]

I've set it all up.... Angle of what's it has been set, had a shim tastic time on it on it, new piston with teeth made from supermans shit, big fat wire all over the place and I've got a new one to drop in as soon as this one goes bang haha

[Sitting Duck]

word of strong advice....

 

test on 7.4v first - especially if a neodym motor is in there

(or high speed gears - if using both neo and 13:1 then I advise ordering up new parts anyway - even on 7.4v coz that could hit 30)

 

whatever she is firing at - BPS app or record sound and count spikes on pc etc.......

 

then get a rough idea what rof is on 7.4v first

11.1v will be 50% more.....

 

if hitting 20rps on 7.4v you will expect to hit aprox 30rps on 11.1v

 

Warning 25+ very slight risk but 30 good chance of PE

(depends on spring strength returning piston faster/slower and also weight of piston - lighter is faster return/ swiss cheese crap etc..)

 

if you used a plastic toothed piston it will just strip

but all metal rack - no weak point to shred and it will really go bang due to all metal teeth gears etc.....

 

you could smash your piston to f*ck AND YOUR GEARS AND YOUR MOTOR PINION GEAR IF ALL METAL ON 11.1v

no $hit - it can happen if you go too nutz without homework on stock m100 or m105 springs

 

luckily I learnt the hard way but with plastic teeth shredding, now I have a rough-ish idea what to expect

so I got a reasonable idea of when I can and when I can't use all steel piston rack

(built up a collection of boned pistons to attain this knowledge of what NOT to do)

 

faster n faster stuff at 30+ has to have shortstroking and M110 - m120 is safer with 2 teeth removed

I got a rough maths table I think that works out about right - will know more as I build n bone more

[Lozart]

 

 

it is when you rewire with thicker wire + deans that the fet comes into its own and it is the other bits that give the faster response

not the mosfet - the fet just allows us to safely switch higher juice for heavier loads on juicy motors etc....

 

That is where the trigger response comes from - not the fet itself

the fet just manages the bigger juice safely keeping your contacts looking good rather than deep fried

 

That's....not entirely true. The capacity to switch larger currents is part of what makes the FET useful as it prevents all the current going through the trigger contacts which can then arc and lead to poor switching and conduction but it's also the ramp rate of the FET that makes the trigger response better. You could JUST fit a hardwired FET using all the original wiring and get a much improved trigger response because the FET can go from 0 to full current far quicker than a mechanical switch. Granted if you combine this with better wiring, Deans connectors etc then the trigger response will be better still but don't make the mistake of thinking that's where the greatest benefit in switching speed comes from.

[Dannn]

With 11.1 im getting around 40 odd per second , but that's testing it with a crappy iPhone app..I'm going to short stroke it with an m120 I think

Do you think plastic teeth are the way to go on really high speed stuff so only that goes bang ?

[Sitting Duck]

Not gonna get into a debate on it but fet is an additional device with additional wiring often sited further backwards....

then the current would flow from the fet to the motor after the fet's own delay or switch on time even in nano/milliseconds

 

it prevents trigger arcing/carbon which would cause resistance etc in switching

 

but like for like as you wouldn't fit a mosfet when the trigger contacts were shot

you would replace switch - but on clean good contacts under stock conditions at least

the fet does not in my mind improve trigger response....

 

as stated above additional device, additional wiring and has its own delay or switch on time

 

burnt out contacts are different - the point I am making is that many people assume the mosfet is improving trigger response

it on its own is not - it is safely allowing the use of higher juice to the motor using thicker wire/connectors

 

take two exact brand new guns and a soldering iron........

 

fit just a mosfet to one gun and to the other fit deans instead of small tamiya to other gun & battery

 

Then dean's gun will show trigger response than the mosfet only gun

 

maybe in time as carbon builds up on deans gun this may get so bad in terms of resistance the mosfet gun triggers faster

 

but like for like new clean contacts the mosfet will not show any improvement in my mind like I stated above

 

trouble is even if it did provide a smidge more, then often people would take it that most of the response must be down to the fet

it is not it is when all the items are upgraded and the fet operates to prevent additional resistance building up at switch

that trigger response is improved and maintained through the larger wire/connectors with little resistance

 

The mosfet is there as I said to prevent resistance taking place - on its own it does not in my book when fitted improve response

 

over time it helps maintain trigger response - I will admit that

but I can't see how on its own with new contacts the response will be improved in the fet Vs deans gun scenario