Multisim and Ultiboard

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Moset model questions and why i can't turn on a foolish LED

Hello

 

Im very simply experimenting with the mosfet model in multi sim

 

Right now im using a generic LED and the generic n chan mosfet

 

I cant get any current flow and i dont know why

 

The threshold voltage is set to 0 in the model so with a 5volt VGS it should turn on no problem. Yes i know the LED needs a resistor in real life. Im lazy and since the LED model can take 100s of amps in the sim with out "blowing" i dont care. Its just there to show me when the mosfet turns on or not. 

 

Can someone tell me why i have no current flow in this model 

 

Thanks

Screen Shot 2016-02-20 at 1.26.00 PM.png

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This is happening becuase of the current that this particular LED requires, and the model of Mosfet that's being used. Because of the Mosfet model that this generic device has, the current that goes through it is not big enough to turn on the led.

 

For these partivcular components you can either change the current required by the led, or change the parameters of the mosfet so that it would have a larger current.

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