TECHNICAL SUPPORT
Published 2026-03-29
Many friends have encountered such an embarrassing situation when playing robots or DIY projects: the board restarts as soon as theservomoves after the wires are connected, or theservosimply does not respond. Eighty percent of these problems are caused by the power supply failing to keep up. Today we will talk about this classicservo, how much current it works at, and how to choose a reliable "energy package" for it.
The operating current is not a fixed value, it is more like a changing interval. When idling, it actually saves power. The general current is about 200 to 400 milliamps, which is 0.2 to 0.4 amps. At this time, it spins very easily and there is no load, so the current demand is not large, and many entry-level power supplies can handle it.
But once it starts doing work, such as if you use it to drive a robot's big arm, or control the steering of a somewhat heavy model, its current demand will instantly skyrocket. Normal operating current is typically between 800 milliamps and 1 amp. If you want to maximize its "power", then you have to look at its "explosive power".
One word should be highlighted here: stalled current. This is the time when the servo is the most "hungry". You can imagine that you are pushing a box that cannot be pushed with all your strength, and all the muscles in your body are tense. When the steering wheel is stuck, or the load is too heavy and cannot turn, its current will instantly rush to 2.5 amps, or even reach 2.8 to 3 amps in a short period of time.
This is not meant to scare people. Many of my friends' projects failed during key actions because they did not take into account the "impact current" at this moment. If your power supply can only stably output 1A, the voltage will be instantly pulled down at the moment of stalling, resulting in insufficient power supply to the control board and a direct reset. So, understanding this peak is critical.
You must want to ask, how much should I design the power supply when I actually use it? Here is a safer method: Don’t just look at the average current of a single servo, look at the sum of the peak values that all servos in the project may reach at the same time. For example, if you build a four-legged robot and use 8 of them, it is impossible for them to stall at the same time, but you have to consider the most extreme movements.
The usual estimation idea is to reserve 1.5 to 2 amps of peak capacity for each servo. But if you are using a servo control board with a large number of channels, and it is common for multiple servos to operate at the same time, then the total current is best designed according to the sum of the "maximum operating currents" of all servos. For example, for 8 servos, prepare the power supply at a peak value of 8 to 10 amps, so as to ensure nothing goes wrong.
A common pitfall for many newbies is to directly use the 5V pin on the development board to power the servo. We have to make this clear, don’t do this! The power chip on the development board usually can only provide a few hundred milliamps of current. If you connect one, if it moves slightly, the board will have to restart, and it may even burn out your computer's USB port.
The correct approach is: let the power supply go separately. The servo should be connected to an external power supply with sufficient power alone, such as using a voltage stabilizing module with a 12V adapter, or using 2 to 3 18650 lithium batteries connected in series. Then, connect the ground wire of the servo and the ground wire of the control board together to ensure that the signal reference is consistent. This is both safe and stable.
Let's do something hardcore. If you have a multimeter or current clamp on hand, you can test it yourself. In the no-load state, the ammeter reading will be stable at about 0.2A. When you give it a command to turn it quickly, you will see the current jump to 0.8A to 1A instantly. At this time, if you hold the steering wheel with your hand, the ammeter pointer will immediately rush upward, directly exceeding 2A.
What does this mean? The instantaneous response is very sensitive and the current fluctuates greatly. For projects that pursue ultimate performance and stability, such as competition robots and industrial-grade models, in addition to looking at the current, the response speed of the power supply must also be considered. A high-quality voltage stabilizing module that can quickly respond to changes in current is sometimes more important than simply high current.
Providing sufficient current is not only to make the rudder move, but also to make it "live" for a long time. If you think about it, if the power supply is insufficient and the servo is in a "not full" state for a long time, the motor and driver chip inside it will have to struggle all the time, which will increase wear and generate more heat. When the temperature is high, the strength of the plastic gears inside the steering gear will decrease, and the gears will appear empty or even tooth-swept.
On the contrary, when you give it a well-reserved power supply, it will move crisply and neatly every time, the motor will not hold back its strength, and the internal circuit will be more stable. Therefore, when we invest in a good power supply, we are actually investing in the life of the steering gear. Many times the steering gear breaks down quickly, not because of poor quality, but because we don't give it enough "food".
Have you ever encountered the embarrassing experience of the servo twitching wildly or directly "strike" because the power supply was not selected correctly? Welcome to share your car rollover stories in the comment area, and let’s avoid pitfalls together!
Update Time：2026-03-29
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