I am new to electronics, and still tying to fully wrap my head around MOSFETs. I have a few questions about controlling a 12v MOSFET using only 5v to the gate, and an incredibly small amount of current.
Here's the situation: I have a 48V power supply which I am converting down to 12V, with a maximum 33A output current. Connected to this 12V output current, is a 12V motor, and an Arduino. I would like to control the motor using one of the Arduino's PWM ports, and a MOSFET, to minimize current draw through the arduino.
Unfortunately, the Arduino's PWM ports can only provide 5V. The MOSFET that controls my motor will (I think) need to be 12V, and what I have read on the subject tells me that controlling a 12V MOSFET with a 5V gate leads to... Bad things. That is my first question -- what will happen if I flat out try to do this?
My second question is this:
How can I create a circuit that will allow my Arduino to control the 12V MOSFET using a 5V, 4-to-40 milliamp current, while still having the MOSFET reacting quickly enough to allow for PWM to reach the motors? What are the specifications of MOSFET that I will need to do this?
The most important question is, of course, what are the mechanics behind all of these things? Talking to people, I hear them talking about using a transistor as a "low impedance source", and to be honest, I don't understand what they mean. How does that play in the whole thing?