Motor Comparison
Motor Comparison Chart
Throughout this course, you have worked with three different types of motors. Each one has different strengths and is used for different purposes.
| Brushed DC Motor | Hobby Servo | Stepper Motor | |
|---|---|---|---|
| Motion Type | Continuous rotation | ~180° positioning | Discrete steps (full rotation possible) |
| Control Method | PWM speed + H-Bridge direction | PWM position signal | Coil sequencing |
| Precision | Low — no position feedback | Medium — set angle, not exact steps | High — exact step count |
| Cost | Cheapest | Mid-range | Most expensive |
| Complexity | Simple (2 wires + driver) | Simple (3 wires, built-in driver) | Complex (4+ wires + driver board) |
| Common Uses | Fans, toys, wheels, pumps | Robot arms, RC vehicles, pan/tilt cameras | 3D printers, CNC machines, camera sliders |
When to Use Which Motor
Use a brushed DC motor when:
- You need continuous spinning (fans, wheels, propellers)
- You only care about speed and direction, not exact position
- Cost is a concern
Use a hobby servo when:
- You need to hold a specific angle (steering, robot joints, levers)
- You want simple wiring and control
- 180 degrees of motion is enough
Use a stepper motor when:
- You need precise positioning across many rotations (3D printer head, CNC drill)
- You need to know exactly how far the motor has moved
- You can handle the extra wiring and programming complexity
Tip
There is no single “best” motor. The right choice depends on what your project needs. A toy car uses DC motors for the wheels and a servo for steering — two different motors in one project!
Quick Review
For each scenario below, decide which motor type would be the best choice and explain why:
- A robot arm that needs to pick up objects and place them precisely
- A desk fan that spins at adjustable speeds
- A 3D printer that moves a print head with 0.1 mm accuracy
- A remote-control car’s steering mechanism
- An automatic pet feeder that dispenses food by rotating a wheel
What You Learned
In this course, you explored:
- Brushed DC motors — how they spin using magnetic fields, how to control speed with PWM, and how to reverse direction with an H-Bridge
- Hobby servos — how they use a PWM signal to hold a specific angle, and how their built-in gears and feedback circuit work
- Stepper motors — how they move in precise steps by energizing coils in sequence, and how a driver board manages the power they need
Each motor converts electrical energy into motion, but they do it in different ways that make each one ideal for specific jobs.