What Transistor to use?

Discussion in 'Homework Help' started by Dusaro, Jun 29, 2011.

  1. Dusaro

    Thread Starter New Member

    May 25, 2011
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    0
    In school I need to make barrier arm using a servo and a picaxe.
    I am using a pickaxe 08m and a Esky Digital Servo EK2-0508 (000155).

    I am not sure on what transistor I should use?
     
  2. wayneh

    Expert

    Sep 9, 2010
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    3,024
    Are you just turning it on and off, not sending some limited current? If so, I'd go with an N-channel MOSFET, probably a logic-level one. (A regular MOSFET needs ~12v to turn fully on). Pick one rated for ~4X more current than your servo needs. A MOSFET will offer virtually no resistance when turned on, whereas a BJT will drop ~0.7v across itself, and will also require a base current.
     
  3. Dusaro

    Thread Starter New Member

    May 25, 2011
    3
    0
    We must make a Electronic barrier arm using a Servo.
    We need to use an LDR then through the picaxe we need to open it when the LDR is shaded and close when it is not shaded.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,086
    3,024
    Perhaps you should post a schematic for review and see what folks think. Few here are excited about doing your homework for you.
     
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