Calculate resolution and understand wiring for 2 phase 4 wire micro stepper motors. A complete guide on specifications, control, and typical applications.
Why 2-phase 4-wire is the standard for miniature precision tasks.
Micro steppers (commonly 6mm to 15mm diameter) with 18° step angles achieve sub-millimeter precision when paired with a lead screw (e.g., camera lens focus mechanisms, medical micro-pumps).
A 2-phase 4-wire configuration utilizes 100% of the copper winding, generating significantly more torque than a 5-wire unipolar equivalent (which only energizes 50% of the coil).
Due to low coil resistance (10Ω-40Ω) and 100mA-500mA current requirements, a dedicated bipolar H-bridge driver is mandatory to prevent microcontroller damage and manage heat.
Baseline parameters for 2-phase 4-wire micro steppers in common applications.
| Parameter | Typical Value | Application Note |
|---|---|---|
| Rated Voltage | 3.3V - 5V DC | Often driven via current-limiting drivers at higher voltages |
| Current per Phase | 100mA - 500mA | Varies by diameter (e.g., 6mm vs 15mm) |
| Coil Resistance | 10Ω - 40Ω | Low resistance requires dedicated drivers |
| Step Angle | 18° (20 steps/rev) | Common standard, often geared down for precision |
| Common Diameters | 6mm, 8mm, 10mm, 15mm | Micro scale footprints for compact devices |
Why 4-wire bipolar dominates the miniature stepper motor market over 5-wire unipolar variants.
| Feature | 2-Phase 4-Wire (Bipolar) | 5-Wire (Unipolar) |
|---|---|---|
| Coil Utilization | 100% (Full winding energized) | 50% (Half winding energized) |
| Torque Output | Higher (Maximum for motor size) | Lower |
| Drive Complexity | High (Requires H-Bridge driver) | Low (Simple transistor switching) |
| Efficiency | Higher (Better torque-to-weight ratio) | Lower |
Micro steppers often lack standard color codes. Use this method to wire them safely without a datasheet.
Set to resistance (Ohms). Test wires. A reading of a few Ohms (e.g., 10-30Ω) indicates a pair (Phase A). No continuity means they are on different phases.
The remaining two wires should also show resistance, forming Phase B.
Connect Phase A to A1/A2 and Phase B to B1/B2 on your stepper driver.
If the motor spins backwards, swap the two wires of ONE phase (e.g., swap A1 and A2).
Coil Pairs Visualization
The specifications and conclusions on this page are compiled from verified industry documentation.
Bipolar (4-wire) motors utilize 100% of the winding compared to 50% for unipolar, resulting in up to 40% higher torque density.
Industry Motion Control Technical Guides
Standard coil resistance values (10Ω-40Ω) and phase current limits (100mA-500mA) for sub-15mm diameter motors.
Hardware Datasheet Aggregates
