TECHNICAL SUPPORT
Published 2026-03-29
Have you ever encountered this situation: the Tower Pro Microservo9G SG90servoyou bought keeps shaking as soon as it is turned, or it cannot carry the small parts you want at all? In fact, the answers to many questions are hidden in the data sheet called "." Don’t be frightened by this German word. Today we will break it apart and talk about it, so that you can feel confident when using this small steering gear in the future.
The first thing you should do when you get theservois not to rush to connect it, but to check its rated voltage. SG90 generally works between 4.8V and 6.0V. Many novices directly use 7.4V lithium batteries, and the result is a burst of smoke. The torque parameter is also very important. It is about 1.5kg·cm at 4.8V. This force is just enough to turn a small robotic arm or camera gimbal. No matter how large the load is, it is really powerless.
The speed parameter cannot be ignored either. At 4.8V, it can rotate 60 degrees in 0.12 seconds. If you are working on a project that requires quick response, such as a small robot playing football, this speed is barely enough. Another parameter that is easily overlooked is the dead zone width, which is about 5 microseconds, which means that it will not move erratically even if the control signal fluctuates slightly, which is particularly friendly to scenes with high stability requirements.
Don’t just glance at the “dimension diagram” in the data sheet. Many people fail to see the dimensions clearly, and as a result, the servo cannot fit into the bracket they designed. The dimensions of the SG90 are approximately 23mm long, 12mm wide, and 29mm high. The thickness of the upper ears (mounting ears) are also marked. Use a caliper to check before opening holes, which can save time in reprinting the shell. It also weighs 9 grams. Even though it is light, in weight-sensitive projects such as drones, every gram must be counted.
The pulse width range is the core control information. The manual will tell you how many microseconds correspond to 0 degrees, how many microseconds correspond to 90 degrees, and how many microseconds correspond to 180 degrees. The standard SG90 is generally 500 microseconds to 2400 microseconds, but there may be differences in different batches. It is best to use an oscilloscope or measure it yourself. Remember, don’t think that all servos have a uniform 1500 microseconds at the neutral position. Only by fine-tuning the angle range in the code during actual debugging will your mechanical movements be accurate.
The most common reason for burning the servo is stalling, that is, the servo continues to send rotation signals to it even after it has been turned all the way. The data sheet does not clearly state how much the locked-rotor current is, but in actual tests it can reach more than 1 amp, and the IO port of your microcontroller can supply tens of milliamps at most, so it must be powered by a separate power supply. It is recommended to equip each SG90 with an electrolytic capacitor of 100 to 470 microfarads, connected in parallel at both ends of the power supply, which can effectively absorb peak currents and prevent reset due to voltage dips.
Another thing that is easily overlooked is signal line voltage matching. If you use a 5V microcontroller, it is no problem to connect the servo signal line directly; but if you use a 3.3V development board, such as ESP32, the signal high level is only 3.3V, and some servos will not be recognized. The solution is simple, add a level conversion module, or use two resistors to divide the voltage to make a simple boost circuit. The minimum threshold for a logic high level is generally stated in the data sheet, and you can find the answer by looking through it.
Many friends asked: I want to use it to make a mechanical dog with a servo for each leg. Is that possible? Frankly speaking, the torque of 1.5kg·cm is only suitable for lightweight and small projects, such as a simple two-degree-of-freedom gimbal or a mechanical claw made of cardboard. If you want to make a joint that needs to lift hundreds of grams of weight, it is recommended to upgrade directly to a metal tooth servo like the MG995. But the SG90 is cheap and lightweight. It is a perfect partner for steering remote control cars and controlling the rudder of small models.
In terms of speed, 0.12 seconds per 60 degrees is pretty good for most DIY projects. But if you are pursuing faster actions, such as the triggering of the ejection mechanism, you can consider increasing the voltage to 6.0V, so that the speed can be slightly increased to about 0.10 seconds. However, it should be noted that long-term overpressure operation will accelerate the wear of the internal plastic gears. The recommended operating range given in the data sheet has a margin. It's okay to step on the boundary occasionally, but don't take it as the norm.
Don’t download PDFs from unknown sources from Baidu Wenku, which often have missing pages or mislabeled parameters. The safest way is to go to Tower Pro's official website and enter "SG90" in the or column to search for the original data sheet. If you find it difficult to read in English or German, you can find some formal electronic component malls in China, such as Lichuang Mall. There is usually a verified download link to the specification sheet under each product page.
Another trivia: You can search for "SG90 Chinese version". Some kind people in the open source community have translated the core parameter table. But remember to compare it with the original version, because the translation occasionally misses important notes, such as small words such as "Torque is measured at 4.8V". After getting the manual, focus on the two chapters " " and " ". You can find answers to most of your questions in use there.
There are actually three wires to control the SG90: red is connected to the 5V power supply, brown or black is connected to ground, and orange is connected to any PWM pin. Use it first when writing code
If you find that the servo shakes badly when turning, it is likely that the power supply quality is poor. Try using two 18650 batteries connected in series and adding a voltage stabilizing module to supply power separately. Do not share the 5V from the USB port with the microcontroller. In addition, the PWM frequency recommended in the data sheet is 50Hz, which is a period of 20 milliseconds. The library defaults to this value, and you do not need to set it additionally. After mastering these few tips, your small servo will be able to complete every action stably.
Have you ever encountered a "rollover" experience in a project because you didn't read the data sheet? Welcome to share your stories in the comment area, or tell us what interesting things you want to use SG90 to do. If you think this article is helpful to you, please give it a like so that more people can see it, and don’t forget to forward it to your friends who are tinkering with servos!
Update Time：2026-03-29
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