I have one of those, tried and gave up. I like your idea of using the connected resistor. It seems like it would have plenty of stability. I may have to give it another shot.
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I have one of those, tried and gave up. I like your idea of using the connected resistor. It seems like it would have plenty of stability. I may have to give it another shot.
Remember that the mosfet will be switching the NEGATIVE, hopefully that's the leg you have it on.
No way would I attempt to use the tiny 8 pin mosfet you have, not due to it's fitness but that package takes a deft touch, good eyes, and some quick soldering. It's just so much easier to use a 3 pin TO-220 package. There are many that will work in the $1 to $3 range. Just as long as the Gate Threshold Voltage is 2.5V or less.
Here's bigblue's original schematic, I altered it a bit in hopes of making it clearer.
As far as the resistor value he's showing 47k, in the past following Nuck's example I've used 10k which worked fine. The higher ohms like big's will put a lower current demand on the switch.
Sorry don't take this the wrong way, I just hope you guys can help me clarify something....why on almost every single schematic...do people here MISIDENTIFY the drain and gate pins? I realize its for a line diagram, but it can get confusing when your diagrams visibly are incorrect. When I say that I mean if I were to lay a 3 pin mosfet on the table right on top of your diagram...to match the source pin I would have to lay the mosfet face down(shiny metal back lookin at me) and if I did match the source pin....now the drain and gate are not labelled correctly accoring to your drawing. Every 3 pin mosfet I have ever wired in a 220 package has been pin 1=gate, pin 2= drain, pin 3= source. Basically...if I was wiring a mosfet without a pinout diagram....just by laying it on top of this line diagram and soldering away...this line diagram is 100% wrong. Please for future line diagrams....just draw the diagrams correctly so as to not confuse people who may be new to wiring.
In addition....if the mosfet was laying metal backing side down..smack on top of the picture in this post..with 3 pins facing 3 oclock position. the pinout is as follows
3 pins facing 3 o clock:
top pin= pin 3= SOURCE
center pin=pin 2=DRAIN
lower pin=pin 1=GATE
Please help clarify this wiring thanks in advance
The following picture has the pins labelled correctly according to any and every 3 pin mosfet manufacturer.http://www.fotos-hochladen.net/view/schalter227bhf6xek.jpg
I apologize for sounding like an ahole, but i am trying to figure out when looking up information on mosfets, every cutaway view shows the center pin as a gate....but every datasheet shows pin 1 as gate and every center pin on a mosfet has continuity with the mounting plate....im just confused as hell, any help is greatly appreciated, thanks in advence
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How is my schematic misidentifying? Point out where it is 'visibly incorrect'. The pic you linked is identical . Is that one also incorrect?
Your pic shows a resistor across the Gate and Source, so does mine.
It shows the negative from the battery going to the Source, so does mine.
It shows the Drain feeding the atty, so does mine ( but through the regulator).
It shows the switch feeding the Gate, so does mine.
Symbols used in schematics are not 'pictures', and many mosfets that we can use have far more than 3 pins. Look at the datasheet, identify the G,D,S pins and follow biggies schematic, which I've clearly and correctly marked.
I added the pin designations to help clarify the schematic, and put a graphic of the resitor showing it attached between Gate and Source.
Sorry don't take this the wrong way, but what the hell are you talking about?
I apologize i've been using the wrong mosfet, an irf510, with a gate voltage of 2.5-4v, way too high for whatever reason it wont fire the atty, that was the issue I couldn't figure out who was correct.. manufacturer, line diagram illustrator...pic in the link or what. Got some IRL3103's coming, we'll see how those work. Any reason this circuit couldn't work with a Darlington pair of transistors and a touch switch?
the confusion was this....the IRF510 gate wont work right ...why? no Idea...it will work fine if I short the drain flange to the source pin...atty fires, but no matter what I do to the gate nothing happens. I can jump straight from the battery to the gate...I get zero fire. So here I am second guessing my wiring like mad, when I am wired the exact same way as your schematic, but the wiring is not the issue the issue is the gate voltage requirement being too high and me not realizing this.
I have successfully fired a regulator using an IRF4905. It's a P-channel enhancement, so the gate voltage needs to be lower, not higher than drain voltage.
I'm gonna try a IRL3103.. being delivered today, and I'm also going to try a MJE2955T transistor...its got a gate V req of 1.8 and handles 10 amps. Then I will try a darlington pair, 1st transistor being low power, 2nd transistor being high power. I'm gonna find out which of the 3 configs works best for me and video the ..... to help make it easy for people to see the work from start to finish.
Hi guys,
Need help on this, I have this Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com
It doesnt work on my VV and im thinking it is most likely because im feeding 8.4V on freshly charged 3.7 batts. based on the data sheet i think it seems it doesnt take more then 8V.
Am i right on the reasoning for this? if so, do any of you know which Mosfet is suitable for a VV mod?
Thanks in advance!
I know that this is an old thread but.........
Having played around with the PTR08100w, if you remove the Neg battery wire from the regulator. An Output voltage is still present and an N-Channel Mosfet is useless. In fact it has the opposite effect. From ON to OFF state. The presents of a voltage is there regardless if a Mosfet is wired in or not.
Perhaps it will work by breaking the Positive leg. Unfortunately I don't have any P-Channels on hand to test it out.
I don't know how givesuhe11 got it to work in the PTR08100 with an N-Channel Mosfet.
WillyB, have you tried wiring the circuit you posted? Technically it should work but like I said above. Removing the neg wire still fires up the reg when the pos is connected.
o4_srt is correct.
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Well I just assumed biggies schematic was correct. And givesuhe11 did insist it works per the schematic with an N.
o4_srt is a sharp guy though with a high level of understanding. But he also brought linear regulators into the mix which rules it out as a switching reg only thing. There have been many schematics posted over the years with N channels switching the neg of the regulator. Nuck is switching the neg with an N on his TI Booster. Seems odd that this has never come up before.
What container is this going in? Plastic box, pipe etc. Seems odd that switching at the ground doesn't work right. When you say there is voltage present is it full on or just a small amount?
Maybe a quick wiring diagram?
Hey Willyb, thanks for the reply. It's the same evercool as I wired several times before. BigBlues. Right now it's in a test board. Full voltage is present when taking off the neg to the reg
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