A Brief Introduction to the 20BYJ46 Stepper Motor

Basic Parameters

• Model Significance: The "20" in 20BYJ46 represents the outer diameter of the motor stator, which is 20mm; "BYJ" indicates that it is a permanent magnet stepping motor with a reduction gearbox (the "B" stands for permanent magnet, "Y" for stepping, and "J" for gearbox); "46" is the design sequence number, which is mainly used to distinguish different product versions under the same series.
• Step Angle: The inherent step angle of the motor (before deceleration) is usually 5.625°/64. This means that without considering the reduction gearbox, the motor needs to complete 64 steps to rotate 5.625°, and the actual step angle per step is 5.625° divided by 64, approximately 0.08789°.
• Reduction Ratio: It typically has a fixed reduction ratio of 1:64. After deceleration, the output shaft's step angle is further reduced, which helps to improve the torque of the motor output shaft while reducing the rotation speed.
• Operating Voltage: The common rated operating voltage is 5V DC, which is compatible with most single - chip microcomputer control systems (such as Arduino, 51 single - chip microcomputers) and is convenient for power supply.
• Torque: The output torque of the motor output shaft after deceleration is generally around 10 - 30gf·cm (gram - force centimeter), which is suitable for driving light - load components, such as small fans, pointer instruments, and small door - opening mechanisms.

Structural Features

• It integrates a reduction gearbox inside. The gearbox is composed of multiple sets of plastic gears, which can convert the high - speed and low - torque rotation of the motor's internal rotor into the low - speed and high - torque rotation of the output shaft, meeting the needs of most low - load driving scenarios.
• The motor shell is made of plastic, which is lightweight and can effectively reduce the overall weight of the equipment. At the same time, the plastic shell has a certain insulation effect, improving the safety of use.

Typical Applications

• Household appliances: Used in the damper control of air conditioners, the valve control of small water heaters, and the rotation control of microwave oven turntables.
• Electronic instruments: Applied in the pointer drive of multimeters, oscilloscopes, and other instruments, as well as the position adjustment of small optical components.
• DIY projects: It is a common component in robot arms, small walking robots, automatic feeding mechanisms, and other DIY works, and is often matched with driver modules such as ULN2003 for control.

Control Principle