Switch with BJT or MOSFET in a R/C car project

Discussion in 'General Electronics Chat' started by lefam, Mar 11, 2011.

  1. lefam

    Thread Starter Member

    Nov 30, 2010

    I am working in a R/C car project that consists in hacking the car's remote control to control it with a cellphone. I am using an arduino duemilanove board (with atmega328 MCU).
    The idea is to send commands to the remote control using the arduino. In fact, what the arduino should do is close some switches in the remote control.

    I am in doubt if I should switch using a BJT transistor or a MOSFET one.

    I have seen on a website that the BJTs are better for amplifying, while the MOSFETs are good in switching.
    Does it matter using one instead of the other? Or doesnt it matter?

    Thank you!!!
  2. kingdano


    Apr 14, 2010
    the good thing about logic level FET devices is that you get guaranteed saturation (low Rds) with a voltage level, not with a current level.

    i would buffer the output of the uC with a non-inverting 74LVC series buffer and drive a logic level FET like the 2N7002 as a switch.

    BJT's can be used for switches as well, but logic level FETs are very popular.