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Setting up the basic N-Mosfet on EC:
Look at the top left circuit...
This has the default EC Nmos with no setting alterations.
The bar in the Mosfet is not seen.
The default EC mosfet settings VTO is 430mV
Look at its current amps through the non lit LED....zero amps.
Now look at the circuit on the top right....
This has the same settings throughout, but the load is now on the Drain side of the mosfet, with the Nmos Source connected directly to Earth.
Again look at the current through the non lit LED...zero amps again.
Now look at the bottom circuit. The Nmos settings have now been maximised for flow, but I have left the VTO as 430mV just like the other two circuits...LED current is zero, just like the other two circuits.
See the gate volts in all three circuits....430mV
NOW..... move the top left circuit gate v up to 431mV......the LED current stays at zero....with no bar shown.
Now move the top right circuit gate v up to 431mV.....the LED shows a slight current and the mosfet bar half open....a better setup than the left circuit.
Now move the bottom circuit gate bar up to 431mV....the LED shows a full 20mA and the mosfet bar is fully seen.
The bottom circuit is the best choice to simulate a real standard Nmosfet (the LED current flows well once the threshold VTO, ie gate Vth here of 430mV , is passed)....but change the Nmos setting VTO to 3v instead of the 430mV shown here....because that is nearer to a real standard Nmos datasheet VTO equivalent. (A full flow transconductance KP setting here is closer to a real mosfet than leaving that as the EC default...see any datasheet... approx 20A for the first volt rise beyond the Vth).
In reality, a mosfet will not be quite so dramatically good as the bottom circuit suggests, because of the Rds in the mosfet, but that can be adjusted from those basic suggested EC Nmos settings by experienced users. Such further alteration is not really necessary though for basic EC Nmos simulation.
My recommendation when using an Nmos in an EC circuit for switching....put all of the Nmos settings as seen in the bottom circuit here, but set your VTO to a point where the gate v will toggle either side of that VTO. (Preferably 3v for realism). ...and keep the Nmos Source attached directly to Earth with no resistance between....that ensures that the Nmos VTO is identical to the gate Vth.
More N mosfet detail here http://everycircuit.com/circuit/5230609179082752
See here for P-Mosfet setup http://everycircuit.com/circuit/5691079249887232
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