upgraded FETs

[charliebrown]

Umm...Jshwaa, I kinda already know that...I know the....Oh nvm...

jshwaa, are you on AIM these days? I added you to my contact list but I never see you online...

Chuckster...

[mod_o_matic]

Wow..i basically read all of that and now my eyes hurt -_-;;. Can some one now make a Step by step thing to make and install one of these? And a noob question: With this upgrade i can basically run motars that need more amage..AND higer voltages the 7.2 volts...


Heh, now i gotta find someone in the GTA that can soder it on the PCB..hope i dont mess up :P

[jon.jon]

Originally posted by mod_o_matic
Wow..i basically read all of that and now my eyes hurt -_-;;. Can some one now make a Step by step thing to make and install one of these? And a noob question: With this upgrade i can basically run motars that need more amage..AND higer voltages the 7.2 volts...


Heh, now i gotta find someone in the GTA that can soder it on the PCB..hope i dont mess up :P

Im not trying to be rude but if you just read everything you wouldnt be asking for instructions
and for your second you would already know what you can and cant run with this mod

[Jshwaa]

Wow..i basically read all of that and now my eyes hurt -_-;;. Can some one now make a Step by step thing to make and install one of these? And a noob question: With this upgrade i can basically run motars that need more amage..AND higer voltages the 7.2 volts...

Here's a thread which has info and links that will make H-bridges quite understandable.

H-bridge Info Thread

Here's a thread with a How-to on installing my version of this modification.

H-bridge install How-to

The external H-bridge allows for higher current drawing motors to be applied, if designed right and utilizes powerful FET's. It does not allow for higher voltages. You need a regulator if you want to prevent blowing IC1 and your receiver due to using voltages higher than 8.4V. That's a separate and, in my opinion, non-essential item compared to external FET power. In essence, the external H-bridge more effectively does what the regulator and higher voltage is intended to do....create higher current flow. There's things you can do to motors to help get a gain in the speed department(lower turns on armature), without raising voltage, but you need to have and H-bridge which can support the current induced by having the voltage stay the same and lowering the 'resistance'(turns). You need an H-bridge which utilizes FET's which have low resistance and high power dissipation ratings. The more the H-bridge's FET's are like wire, the better. The best power connection would be to have wire running from cell to motor, and that's it. You can't control the wire, but you can control an H-bridge.

[mod_o_matic]

Beauty..but i can use the other one (the one on this site) instead of that one. This one seems to be for bigger things then what i want..i want something simple and small...so that if i put the wrong motar in (winding messsed up or what not) it wond blow up :P Thanks..i gess i gotta read over it again...

[Jshwaa]

Beauty..but i can use the other one (the one on this site) instead of that one.

Yea, but you're going to have to get a hold of him for an install. I think you're referring to the whoa nelly turbo....in which case, yes, it is smaller. I'm sure the install is much the same though.

[mod_o_matic]

Arighty...plus i can most likly get the parts from a loacal store so it would be easier..
What wattage is you sodering iron?

[mod_o_matic]

Ok..after reading over this AGAIN..i found the page i skipped and now understand what i need to do!
NOW:
What are the posible FET i can use? Can you list the ones that will work with like the name and everyhting asi have no clue what to look for and i am just gonna show it to the dude who own the electronic store..i hope it wont cost more then 10 bux!!!

[Corey]

I just picked up some some power transistors and i was wondering if i could use them in the fet upgrade, heres the link http://www.radioshack.ca/estore/Prod...roduct=2769026

[Jshwaa]

I just picked up some some power transistors and i was wondering if i could use them in the fet upgrade, heres the link http://www.radioshack.ca/estore/Pro...product=2769026

You could use those in place of mosfets, but that particular transistor is a darlington power bipolar junction transistor(BJT), which means that unlike mosfets, they actually consume current to switch on/off, which is a waste of power. Mosfets are the way to go with this application, and you're not going to find decent ones at Radio Shack, that's for sure. Go to www.digikey.com and look for IRF-3205's or IRF-4905's. Those will have waaay higher ratings then anything Radio Shack will carry, and probably cheaper. The only problem with digikey is, if you don't have a credit card, you get charged for orders under $30. And if you gotta C.O.D. an order under $30, forget it. It'd cost too much.

[Corey]

So if i wanted to make a H bridge i would just need four IRF-3205's or IRF-4905's?

[Jshwaa]

So if i wanted to make a H bridge i would just need four IRF-3205's or IRF-4905's?

If your logic is right, you can use any arrangement of 4 transistors, whether they be 4 N channel, 4 P channel, 2 P and 2 N channel, etc. , so yes you can. The xmod's logic is set up so that an H-bridge is made up of 2 N's and 2 P's. If you invert the signal going to the P's, you could put N's there and have an H-bridge driven by 4 N's. Vice versa, if you wanted to make an all P-channel mosfet driven H-bridge. It's better to use all N's though, because N's usually have lower resistance than P's.

[Corey]

Ok, and on you're H bridge there is 4 FET's, what is that other longer chip at the bottom?

[Jshwaa]

That is a 4 channel opto-isolator with NPN transistor outputs.

[Phred168]

Which translates to... in english?