Hi everyone, here is the circuit:
http://www.kerrywong.com/blog/wp-content/uploads/2010/02/controllercircuit.png
from this page
Kerry D. Wong » Blog Archive » A Parallel Port Stepper Motor Driver With Discrete Components
I want to build a similar circuit to control a DC motor with my parallel port, but I have real difficulty understanding the operation of the MOSFETS.
Why is the gate of the each MOSFET connected to the source? I thought the MOSFET was supposed to isolate the controlling portion of the circuit from the controlled. How does one create voltage on the gate when there is no place for the voltage to go? I would have expected a MOSFET to have four terminals, one pair of wires for a small current to flow through causing a large current to flow through the other two wires. Also, why does this even work, wouldnt the current simply flow through the diode, turn right, through the resistor and out to ground bypassing the gate?
Could someone please explain the function of the MOSFETS in terms of electron flow, in this particular circuit?
Thank you!
http://www.kerrywong.com/blog/wp-content/uploads/2010/02/controllercircuit.png
from this page
Kerry D. Wong » Blog Archive » A Parallel Port Stepper Motor Driver With Discrete Components
I want to build a similar circuit to control a DC motor with my parallel port, but I have real difficulty understanding the operation of the MOSFETS.
Why is the gate of the each MOSFET connected to the source? I thought the MOSFET was supposed to isolate the controlling portion of the circuit from the controlled. How does one create voltage on the gate when there is no place for the voltage to go? I would have expected a MOSFET to have four terminals, one pair of wires for a small current to flow through causing a large current to flow through the other two wires. Also, why does this even work, wouldnt the current simply flow through the diode, turn right, through the resistor and out to ground bypassing the gate?
Could someone please explain the function of the MOSFETS in terms of electron flow, in this particular circuit?
Thank you!