IRF510 Mosfet on the B.O.E.

Beau Schwabe

willthiswork89,

Here are a few articles that should help you to understand what a transistor is used for,
and how you can correctly apply them to your circuit.

http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf
http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv23.pdf
http://www.parallax.com/dl/docs/cols/nv/vol2/col/nv52.pdf
http://www.parallax.com/dl/docs/cols/nv/vol4/col/100.pdf




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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

T Chap

you cannot put a resistor in line with the supply to a motor like that and expect it to work. if you are trying to drop the current (which is confusing in the first place), you need some much smaller value resitors that are high wattage. first get a better understanding of mosfets in general before you try to make your motor work. the best way to drop the current to the motor(if needed) is to chop it up with pwm, it is much more efficient to do it that way. you can add pwm to the h bridge on the low side, just google up pwm h bridge or pwm copper circuit but, it is unlikely that you are sending the motor too much current since it isn't moving as you said. since you have two supplies, you may want to run a wire between grounds on each system.

using all n channel mosfest, the gate on the high side must be larger that the source (vdd) by some value(5-7volts? ), i forget the method to calculate it, but there are drivers on the market that do this for you here is one that i use that is great, but there are others, see the parallax link nuts and volts below also:

http://www.irf.com/product-info/datasheets/data/ir2184.pdf
(warning surface mount only available)


read these links too

http://roko.ca/articles/hbridge.php?page=3

http://www.robotroom.com/HBridge.html

http://www.parallax.com/dl/docs/cols/nv/vol2/col/nv52.pdf


yes you can use all n channel mosfets, yes you can use both p and n channel mosfets, but you must understand the principles behind each method, including how you would turn on an n channel on the high side in the first place.

http://www.google.com/search?hl=en&client=safari&rls=en-us&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=mosfet+h+bridge&spell=1

willthiswork89

i dont want to drop the current but i was getting to that there cant be any less current from the battery. basically what i read from all those Nuts and Volts is dont make your own just spend more money and buy one already made. the simplest thing to do, looking at it is to buy relays as i dont care about motor speed, its on or its off. That still doesnt solve the problem that i couldnt get it to work right which will sit in my mind until I do, do i guess i either figure it out or buy relays and use transistors to run it. Im glad you guys are helping me, alot of places would have been done a long time ago.

I suppose i cant know what i dont read so that would explain alot of the reason im pretty much oblivious to the time ans knowledge it takes to make a simple dc motor be able to run back and forth.

Tom Walker

I seems like a measure of the frustration in this thread is due to an incomplete understanding of the principles involved in your request...particularly those related to basic electronics theory. In that regard, the "What's a Microcontroller?" text is a good start.

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Truly Understand the Fundamentals and the Path will be so much easier...

willthiswork89

ive read that and boebot book and ir remote, all fully read mr. walker

PJAllen

· Electronic Principles, by Albert Paul Malvino, Ph.D; it's a textbook.·
· You can't just go whumping thus and sundry together and make it all·"work."· N-channel, P-channel, salt-block...· You've been doing a lot of flailing about, mate, grasping for straws; that's not working at all.
· You might consider taking things incrementally; first you crawl, then you walk, then you run.

willthiswork89

thank you mr. Allen ive always been known to take on calculus before i new algebra not literally but you get my point. again i have learned SO MUCH from you guys working on this. i didnt even know what that transistor was before i started working on this. anyways ill goto the library tomarrow and see if that book is available!