# Power MOSFET's



## Dr Morbius (Sep 21, 2004)

Anyone know of a good source with good prices on power MOSFET's? I've seen some on-line for around 5 bucks ea, but would rather pay less. 
Specifically, I'm looking for NTE2382 N-channel AND NTE2383 P-channel MOSFETs . ANY help would be appreciated. I'm building some high power servos from wiper motors.


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## Otaku (Dec 3, 2004)

Jameco has the 2382's for $3.59 each. No 2383's, though.

http://www.jameco.com/webapp/wcs/st...uctId=272954&searchValue=nte2382&searchType=m


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## Dr Morbius (Sep 21, 2004)

Thanks Otaku, it's a start. I appreciate it.


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## Sickie Ickie (Jun 20, 2006)

what's a mosfet do?


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## eanderso13 (Apr 10, 2008)

It's a type of transistor. Can be used for amplifying power, audio signals, etc...or as a type of switching device.


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## Dr Morbius (Sep 21, 2004)

It looks like I'm not going to pay less than around 4 bucks ea for these. I need 4 per servo, which means in addition to the wiper motor and servo board, I'm looking at about 25-30 bucks per high power servo. Not too bad considering what it it'll do. I can live with that.


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## Evil Bob (Sep 1, 2005)

Cool Doc! What are you building?

I used to work in a GaAs FET foundry.

Formally Bob A. Fet


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## Scottzilla (Jun 13, 2007)

Digikey = no joy.
Mouser = $9.35

I'm no help.


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## pshort (May 6, 2008)

It's a bit late now, but I'd look for other parts. The NTE parts are almost always many times more expensive than similar parts from other manufactus.

If you need that much current, the IRF520 and IRF9530 look like pretty fair replacements for the NTE2382 and NTE2383, and they cost around $1 each from mouser.com. FWIW.


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## Dr Morbius (Sep 21, 2004)

Pshort thank you very much, and no, it's not too late, I very much appreciate it! So these replacement MOSFETS will do the same job? They have the same specs?


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## Dr Morbius (Sep 21, 2004)

Bob Andrews said:


> Cool Doc! What are you building?
> 
> I used to work in a GaAs FET foundry.
> 
> Formally Bob A. Fet


LOL! Cool name....Read the first post...ok, I'll say it here. I'm buiding high power servos out of wiper motors.


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## pshort (May 6, 2008)

These parts should do the same job. The specs for the IRF520 are almost identical to the NTE2382, in fact mouser lists the NTE as a substitute for the IRF part. The specs for the IRF9530 are slightly better than those of the NET2383, so it should work just fine. If you are using someone else's design, you might want to discuss it with them. However, I would be extremely surprised if any of the slight differences in specs (or the slight mis-match between the N-Ch and P-Ch parts) matters in the least.


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## Evil Bob (Sep 1, 2005)

Dr Morbius said:


> LOL! Cool name....Read the first post...ok, I'll say it here. I'm buiding high power servos out of wiper motors.


:zombie:No duh, doc. What are you building that requires you to build high power servos out of wiper motors?


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## perdidoman (Dec 2, 2007)

*Thank you BA, that's my question. It sounds cool, what ever it is.*


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## Dr Morbius (Sep 21, 2004)

Well, I didn't want to spill the beans on this until I was sure it could work, but what the heck. It's a fully functional autonomous structure for the purpose of actuation. There. I said it. Happy now? LOL!


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## Dr Morbius (Sep 21, 2004)

Ok, seriously, it's for a witch prop. I'm using them for full arm and hand motion. The arms will be PVC and actuated through brakeline cables.


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## perdidoman (Dec 2, 2007)

*Sure, I understand now... LOL
You the man. Do keep us posted if it works.*


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## Dr Morbius (Sep 21, 2004)

I will.


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## DeathTouch (Sep 6, 2005)

Now where is the video and pictures?


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## Dr Morbius (Sep 21, 2004)

I haven't built them yet!! I'm still sourcing for parts, hence the purpose of this thread...Good gawd of cheese! LOL!


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## Dr Morbius (Sep 21, 2004)

Hey pshort, which IRF520? I see about 5 different ones from different mfgs. Does it matter?


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## DeathTouch (Sep 6, 2005)

Well then get going then. What are you waiting for? Besides parts. LOL


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## pshort (May 6, 2008)

Are you looking at the mouser.com site? Only two of them are in stock, although I don't think that it matters for your purposes.


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## Dr Morbius (Sep 21, 2004)

Yes I was. Ok, I saw the two, one was the NTE Goldbar Mosfet...Jeez, 10 bucks? What a ripoff. Thanls for the alternatives, pshort, this makes my plans much more feasable.


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## Evil Bob (Sep 1, 2005)

Dr Morbius said:


> Ok, seriously, it's for a witch prop. I'm using them for full arm and hand motion. The arms will be PVC and actuated through brakeline cables.


Seriously Bob, what's it for?


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## Death Master (Jul 1, 2007)

Hay Doc are you making those servos from the radio control lawn mower site? If so just to let you know I used solid state relays instead of MOSFETS to make my super servos and they work great.


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## Dr Morbius (Sep 21, 2004)

Cool, but I'd rather pay a buck per MOSFET than 6 per relay. If by some chance I come across some freebies, I'll compare notes with ya.


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## Dr Morbius (Sep 21, 2004)

Bob Andrews said:


> Seriously Bob, what's it for?


Ok, you got me...It's for a time machine.


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## Evil Bob (Sep 1, 2005)

Dr Morbius said:


> Ok, you got me...It's for a time machine.


Ha! I knew it.


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## Dr Morbius (Sep 21, 2004)

Ok, you got me...It's for a time machine.

It WORKS!


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## Sickie Ickie (Jun 20, 2006)

Didn't you say that before?


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## Dr Morbius (Sep 21, 2004)

It's a time machine thing.


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## Sickie Ickie (Jun 20, 2006)

Didn't you say that before?


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## Death Master (Jul 1, 2007)

Ok Dr. Morbius, its been awhile, did you get your time machine to work?


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## Dr Morbius (Sep 21, 2004)

Death Master said:


> Ok Dr. Morbius, its been awhile, did you get your time machine to work?


DM, I'm needing a burned out servo preferably free from a generous soul. I would pay shipping, the thing is I can't bear to part out a perfectly good servo (I have some, all work fine) to gut for this project. I may just break down soon and sacrifice one, but I really don't wanna. Can anyone help out a poor American with a burned out servo they don't need no mo'?


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## Death Master (Jul 1, 2007)

Don't do that Doc. check this out...http://www.lynxmotion.com/Product.aspx?productID=648&CategoryID=52
This is what I use, I have taken good servos apart before for the guts, but man did that hurt. I'm working on a control board for using pneumatics instead of motors for powering my servopneumatic animatronics, so I can have position, and speed control over the air cylinders, using VSA to control it all.


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## heresjohnny (Feb 15, 2006)

Thats cool Death Master. I have read about using h-bridges to control DC motors. Is the 5k pot they show linked to the servo output to sense position?


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## Death Master (Jul 1, 2007)

Yes Heresjohnny, I mounted the pot in the pivot points of the joints for feedback, and I'm using an H bridge to handle the 24V solenoids.


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## Dr Morbius (Sep 21, 2004)

5k pot they show? Where? can this be used in place of a servo circuit? Where does the motor outputs go? Are the 3 wires used to connect to a servo controller?


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## Death Master (Jul 1, 2007)

Dr. M, you add the 5k pot to the three wires showing, It is a servo circuit, you have to add the 3 pin connector, here is a wiring digram.










Hope this helps.


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## Zombie-F (Apr 12, 2004)

Dr Morbius said:


> Anyone know of a good source with good prices on power MOSFET's? I've seen some on-line for around 5 bucks ea, but would rather pay less.
> Specifically, I'm looking for NTE2382 N-channel AND NTE2383 P-channel MOSFETs . ANY help would be appreciated. I'm building some high power servos from wiper motors.


If you work for a company that deals with electronic devices, you may be able to contact the manufacturer directly and ask for a few sample pieces. Most companies will put up a few pieces for free if there's the prospect it could be used in a product.

If not, come up with a "dummy company" and do the same as described above.


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## heresjohnny (Feb 15, 2006)

Doc, read the directions man! (LOL) So I take it you hook this thing up to a servo controller and a 5k pot, use the motor output as an input to the MOSFET, which will drive the wiper motor? Cool idea, you'll have to let us know how it goes Doc.


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## Dr Morbius (Sep 21, 2004)

Death Master said:


> Dr. M, you add the 5k pot to the three wires showing, It is a servo circuit, you have to add the 3 pin connector, here is a wiring digram.
> 
> 
> 
> ...


Wow! This is perfect..thank you! Now if it costs less overall than building one from a burned out servo and MOSFETS, I'll definitly go this route. Pretty neat little board!


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## Dr Morbius (Sep 21, 2004)

Ok, I broke down and bought the Hbridge. After calculating how much for parts and perfboards, this is a good deal. I'll hook it all up and post the results as soon as it arrives.


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## Death Master (Jul 1, 2007)

Good for you Dr., love to see what you have done with it.


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## Dr Morbius (Sep 21, 2004)

It hasn't been delivered yet, but as soon as it gets here I'll put it together and post a vid of it working (hopefully) under VSA. If it works, I'll need about 8 more for my project...heheh


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## Dr Morbius (Sep 21, 2004)

Der..I need 5k pots, so I ordered them from none other than..RADIOSHACK! Believe it or not, they had the cheapest shipping cost! Go figure.


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## Koumajutsu (Aug 9, 2006)

Was rat-shack not close enough to simply drive to?


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## Dr Morbius (Sep 21, 2004)

Drove to all 7 locations and not a single 5k POT in stock. Oh they had lots of cell phone accessories, but thier drawers of components leave alot to be desired. One spot told me they were no longer restocking electronic components in store anymore. Jesus, what a shame.


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## Koumajutsu (Aug 9, 2006)

That sucks.
Radio Shack's original purpose was to be that place you could go to get electronic components at any time.

Now they're all just Sprint store clones with some cheap RC cars in a corner.

Thank god for the mom & pop electronic shops that are still clinging on.

I'm fortunate enough to have one near my home, and one near my work.

I also know of quire a few others down here in So-Cal. 

If you know of any HAM radio geeks, they might be able to point you to a local shop or two


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## Dr Morbius (Sep 21, 2004)

There is one electronics store in a neighboring town but they fleece you with the prices. They wanted 5 bucks for the same pot. Same price I'm paying with shipping but I won't shop there just for spite.


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## Dr Morbius (Sep 21, 2004)

Do you guys think I will still need MOSFETS with this thing? Is 2 amps enough current to power a wiper motor?


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## Koumajutsu (Aug 9, 2006)

it may be enough, but the FETs wont hurt


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## Dr Morbius (Sep 21, 2004)

I'm primarily afraid of running that much juice through my Parallax board and frying it. Crap, if I still need FETS, then I may as well just rip open a cheap hitec 311 for 9 bucks. Cheaper than the Hbridge I just bought. Any thoughts?


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## Koumajutsu (Aug 9, 2006)

well, it's been my experience that it's never a good thing to run a device at it's maximum current limit. When I was in school, they taught us to select our components based on twice the current our load would require.

the real question is how much current the motor will actually draw when loaded in your design.

if you do little things like counter-ballance your movement points to reduce the amount of torque placed on the shaft of the motor, then you'll minimize the amount of current required in order for the motor to turn.


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## Dr Morbius (Sep 21, 2004)

I hooked it all up, and it does work! I left the POT off of the motor shaft and turned it by hand. The motor turns at powerup, PC on no software running just as a test and the PArallax board sets the servo to center position. One problem..and I think I just need to swap out the ATX power supply for another newer one I have, but at MAX turn of the POT while the servo is trying to center itself, the powersupply turns off like there is a short..I know my wiring is good. I'll try a swap to see if it helps. I'm running 5V through the Parallax board straight through the H-bridge amp to to motor. No heat, looks like the Parallax can handle at least one wiper motor servo no problem. This is interesting, I'll put up a vid later tonight.


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## Dr Morbius (Sep 21, 2004)

Switching out the supply helped ALOT so I know it's a current issue. Here is a vid of my high power servo. Sorry no sound, I was explaining everything while recording, but my capture software didn't get the audio..anyways, I am turning the POT by hand, adjusting the speed and direction with it. When the POT is hooked up to the motor shaft, VSA will control it. The shaft on the motor is very stubby, I'll need to get some kind of coupler to hook the POT shaft to it, and mount it upside down over the motor. So far, this is very promising, and it has exceeded my expectations. I now have the means to animate prop arms and hands. This gonna be so cool.

powerservotest.flv video by DrMorbius02 - [email protected]@[email protected]@http://vid23.photobucket.com/player.swf?file=http://vid23.photobucket.com/albums/b364/DrMorbius02/[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@b364/DrMorbius02/powerservotest


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## hpropman (Jul 27, 2008)

Hey doc, 

What about using a servo to control position of the pot instead of mounting the pot to the wiper motor shaft. once the servo is powered and centered you can center the wiper motor and then control the pot with the servo by means of a coupler. then the wiper motor will mimic the movement of the servo. I know it is more expense because of the 2nd servo but you can use a servo controller board to control multiple servos. It can even be self contained by controlling the servo controller with a microcontroller as opposed to VSA. Just something else to think about. I would think that the mechanical connection might be awkward to use and might get in the way of the wiper arm movement. Also pots come in slide type as well as turn type Just thought I would throw that in in case someone comes up with an idea for that kind of pot.


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## Dr Morbius (Sep 21, 2004)

I never thought of using a servo to control a servo..Interesting idea, if I can't get the POT mounted for some reason, I'll give it a shot. Keep in mind, the power servo won't, when finished, turn 360 degrees. Although your idea is perfect for controlling it in a 360 degree fashion, should I require it. Thanks!


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