Transistor and motors(DC/ stepper/ servo)

 

motors

How each motor are different from one another?

DC motors

  • Keeps moving(rotating)
  • Require polarity change to change direction
  • Can change speed by changing the current
  • When connected to another source, it can cause back voltage, which can be prevented by putting a diode
  • Unable to get feedback on the motor’s position

Gearhead DC motor

  • Useful when requiring power but doesn’t require a lot of speed

Stepper motor

  • Don’t turn continuously, but move in a serious of steps
  • Can turn the motor in very precise control (used in 3D printers and etc)
  • Have high torque when stopped
  • Require polarity change to change direction
  • Unable to get feedback on the motor’s position

Servo motor

  • Can get feedback on the motor’s position(do not have to reverse the polarity)
Controlling High-Current Loads

Different ways of dealing with high-current loads

Relay

  • Mechanical switch(soler than electronical ones)

NPN

  • OFF to ON
  • Works from higher current to a lower voltage(base, Arduino, should have lower voltage)
  • The diode can prevent back voltage(mind the direction)

PNP

  • ON to OFF
  • Works from lower current to a higher voltage(base, Arduino, should have more voltage)
  • The diode can prevent back voltage(mind the direction)

Darlingtons and MOSFETs

  • Compared to NPN or PNP, requires negligible current on the base in order to activate
Lab1

Using a Transistor to Control High Current Loads with an Arduino

Q1. Why is 1K resistor needed?
Q2. Why does diode face “C” direction whether than the other way around?

FQP30N06L