Motors (DC & Stepper)

1. Definition

1.1 DC Motor

A DC motor converts electrical energy into mechanical rotation using direct current.
Think of it as an electric fan without the blades, give it power, and the shaft spins.

DC Motor example

1.2 Stepper Motor

A stepper motor moves in discrete steps, providing precise control over position without feedback.
Instead of spinning freely like a DC motor, it moves in tiny fixed jumps, perfect for positioning systems.

Stepper Motor example

Motor Symbols

Motor symbols

The circles with “M” are generic motors, while the segmented circle often represents a stepper.

2. Features

  • DC Motors: Simple speed control via voltage or PWM (Pulse Width Modulation). (More voltage = faster spin.)
  • Stepper Motors: Controlled via step pulses for exact positioning. (Number of pulses = how far it moves.)
  • Voltage & current ratings. (Match these to your power supply to avoid burning the motor.)
  • Torque & speed specs. (Torque = how strong it is; speed = how fast it spins.)

4. How to Use

Safety Note

Motors can draw high startup current; ensure your driver circuit supports it.
(A motor can briefly pull several times its normal current when starting, this can fry weak drivers.)

4.1 Identify terminals

  • DC Motor: Two terminals. Reversing polarity reverses rotation.
  • Stepper Motor: Multiple coils (4, 5, 6, or 8 wires).
    (More wires = more coil configurations. Datasheet tells you which is which.)

4.2 Driving motors

  • DC motor: Use an H-bridge or motor driver IC. (Like the L293D or L298N.)
  • Stepper motor: Use a dedicated stepper driver (e.g., A4988, DRV8825) to send step pulses.

4.3 Applications

  • Robotics (wheel drive, arm movement).
  • CNC machines (precise positioning).
  • Fans and pumps (continuous rotation).

Common beginner project: Use Arduino to control a DC motor with a potentiometer for speed, or a stepper motor to turn a dial to a set angle.

5. Video Explanation

video coming soon