Replacing npn transistors

[roni21702]

I have a Bridgeport boss 5 machine and it has npn (2N6547) transistors that control the stepper motors. Can these transistors be replaced with mosfets instead. Can someone explain the difference to me.

[ez-cnc.com]

Well they actually could be replaced by mosfet but, its not that easy. Transistors work with a current flow at the base pin, instead Mosfet need a voltage level at the gate pin. what happens is that to drive a transistor what u need to do is apply a certain amount of current, and that will make current flow from collector to emiter. Depending on the size of the transistor it will need more or less current at the base. Mosfets need a voltage to be driven in general if u want them as a switch u need 10V. But the real problem is when switching on a mosfet u need a certain current flow cause the mosfet behaves like a capacitor. So you need to be able to apply a certain amount of current to turn it on(or charge the capacitor), after that there is no current consumption(well there is very little current). So if your transisitor is working as a switch you could get the signal going to the base of the TR and feed it to a mosfet driver and after that a mosfet. So that u get this clear is not a simple take out the transistor and put a mosfet.
There are some mosfets that can be driven by logic levels(5V) and that could be easier to do but i dont know how is your circuit and how the transistors are driven and how big your transistors are.
Hope you get the idea, but it could be done.