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help with a simple MOSFET motor controller. — Parallax Forums

help with a simple MOSFET motor controller.

mjordan_14mjordan_14 Posts: 5
edited 2010-01-07 20:44 in BASIC Stamp
i have a HomeWork Board and i need a way to control two motors both forward and reverse. is there a simple way i can do this with the MOSFET's radio shack sells?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-01-07 20:24
    No

    The MOSFETs that Radio Shack sells are not intended for use with logic circuits. The minimum gate voltage needed for them to conduct enough current for a motor is way above the 5V that the HomeWork Board's I/O pins can supply. There are other MOSFETs that will work, but you won't find them at Radio Shack. You might do better by using ordinary junction power transistors to form what's called an "H-Bridge" which uses 4 transistors to turn a motor on and off and will reverse the direction of the current (and the rotation). Look up "H-Bridge" in the Wikipedia. You can also find sample H-Bridge circuits with a web search. There's one link to a simple H-Bridge circuit on the bottom of the Wikipedia page on H-Bridges.

    Post Edited (Mike Green) : 1/7/2010 8:29:40 PM GMT
  • mjordan_14mjordan_14 Posts: 5
    edited 2010-01-07 20:35
    junction power transistor, like a basic 2N4401 or 2N3904?
  • Mike GreenMike Green Posts: 23,101
    edited 2010-01-07 20:44
    Yes, depending on the amount of current needed by the motors.
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