The SG90 servo motor stands out due to its compact size, simple control method, and reliable performance. It operates using PWM signals, allowing accurate angle positioning while maintaining stability. This article will discuss the SG90 servo motor basics, wire configuration, features, equivalents, selection tips, working principle, and applications.

Catalog

Servo Motor SG90 Basic

The SG90 servo motor is a small and lightweight micro servo designed for precise position control. It is commonly known as a 9g servo, meaning it weighs only around 9 grams. This motor can rotate to a specific angle, typically between 0° and 180°, based on a control signal, making it suitable for controlled motion tasks.

It works using PWM (pulse width modulation) signals. The signal tells the motor what position to move to, and an internal control circuit ensures it reaches and holds that angle accurately. Unlike standard DC motors, the SG90 does not rotate continuously but moves to fixed positions.

The SG90 operates at 4.8V to 6V and provides a torque of about 1.5–2 kg/cm. It has three wires: power, ground, and signal. Its compact size, simple control, and low cost make it a popular choice.

SG90 Wire Configuration

SG90 Wide Features

Compact and Lightweight Design

The SG90 weighs around 9 grams and has a small form factor. This makes it easy to install in tight spaces and suitable for designs where size and weight are important.

Precise Position Control

It uses PWM signals to control its angle accurately. The motor can move to a specific position and hold it steadily without continuous adjustment.

Low Power Operation

The SG90 operates within a voltage range of 4.8V to 6V. It requires low power while still maintaining stable performance.

Fast Response Speed

This servo provides quick movement, typically around 0.1 seconds per 60 degrees, allowing responsive and smooth operation.

Adequate Torque Output

It delivers a torque of about 1.5–2 kg/cm, which is sufficient for light-duty tasks and controlled movements.

Simple 3-Wire Interface

The SG90 uses a basic three-wire system for power, ground, and signal, making it easy to connect and use.

Stable Holding Capability

Once positioned, the motor can hold its angle firmly without drifting, ensuring consistent performance.

Durable Plastic Gear Structure

It features plastic gears that provide smooth motion and reduce weight, suitable for standard usage conditions.

Wide Compatibility

The SG90 is compatible with most microcontrollers and control systems that support PWM signals.

Cost-Effective Solution

It is affordable and widely available, making it a practical choice for many electronic designs.

SG90 Servo Motor Equivalent

Selecting Servo Motor

• Choose from different servo motors based on your project needs

• Most hobby servos operate between 4.8V to 6.5V, commonly at 5V

• Higher voltage can provide higher torque output

• Standard servos typically rotate from 0° to 180° only

• For full rotation, select a 360° servo or modify the motor

• Gear type matters:

- Plastic gears → lighter, suitable for normal use

- Metal gears → stronger, better for heavy or long-term use

• Always consider durability and wear, especially for continuous operation

• Torque is the most important factor when selecting a servo

• Example: 2.5 kg/cm torque (SG90) means:

- Can lift 2.5 kg at 1 cm distance

- Can lift 5 kg at 0.5 cm distance

- Can lift 1.25 kg at 2 cm distance

• Torque decreases as the distance from the shaft increases

• Select a servo motor based on the load and distance in your design

How to Utilize a Servo Motor

Using a servo motor is simple once you understand its three-wire setup and control method. The motor requires a power source, a ground connection, and a signal input. The power and ground provide energy, while the signal wire receives control pulses that determine the motor’s position.

To operate the servo, you need a device that can generate PWM signals, such as a microcontroller or timing circuit. The motor does not rotate freely; instead, it moves to a specific angle based on the pulse width it receives and then holds that position.

The control signal typically runs at a fixed frequency, while the pulse width changes to adjust the angle. A shorter pulse moves the shaft toward one end, a middle pulse sets it to the center, and a longer pulse moves it to the opposite end.

By adjusting this signal continuously, you can control the servo smoothly and accurately for precise positioning tasks.