MOSFETS

When chosing a MOSFET be sure to look at the datasheet to see what voltage is needed to turn on the FET. Looking at the NDT2955 it can turn on Vs-2.6 If the source was at 5V then 5-2.6= 2.4V is needed at the gate to turn off.

Here's some circuit analysis of a MOSFET. Its threashold is at -1.8. You will notice that the P Channel FET turns off 5-1.8= 3.2V In Switchercad the variable to look at is Vto. To see this variable you have to place a FET, right click the part and select a differnt type. You will see some Fairchild parts w/ some others.