Source: https://mokxi.com/parts/servo Updated: 2026-09-27 Part # Hobby servo A pulse width, not a duty cycle. The horn turns to wherever you send it. or see every part - 3 pins - 6 properties Drawn live by the editor's own code, at the size you see it. Reference ## Every one of its 3 pins Pin Role What it does GND Input or output Ground, brown wire. VCC Input or output Supply, red wire. PWM Input Signal, orange wire: a pulse width, not a duty cycle. This part ## What it does A hobby servo, SG90 style, turns its horn to an angle and holds it. Its signal wire does not take PWM in the dimming sense: the servo measures the width of each pulse, about 1 millisecond for one end of its travel and 2 for the other, sent roughly fifty times a second. That is why analogWrite() on an Uno cannot drive one and the Servo library makes the pulse itself. Mokxi’s part times each pulse off the pin’s own edges and walks the horn towards the angle at the datasheet’s 0.1 seconds per sixty degrees, ignores a width outside its window as noise, and holds its position when the pulses stop. The window, the travel and the speed are all properties. What it does not model is current: a real SG90 can pull enough when it stalls to reset the board powering it, and nothing here will warn you about that. How to use it ## How to use a servo with an Arduino Brown to GND, red to 5 V, orange to any digital pin. Then use the Servo library: attach() the pin once in setup() and write() an angle from 0 to 180 whenever you want the horn to move. The library’s calls compile here as they stand; its default pulse window is the SG90’s 1000 to 2000 microseconds, and attach(pin, 544, 2400) gives the upstream library’s. On a real bench, give a servo its own 5 V supply once it is carrying any load, and join the grounds. Part pin Board pin GND (brown) GND VCC (red) 5 V PWM (orange) Pin 9 ESP32Servo.h is the same class under the name ESP32 tutorials use, and the ESP32-C3 servo example drives one from a hardware PWM channel. Click to open it in the editor This is the simulator itself, running here. Click anything to open it in the editor. Open this project in the editor Read the full tutorial The Servo library sweep, as it compiles here Reference ## The 6 properties you can set Property Default What it means min_pulse 1000 the pulse widths for the two ends of travel, 1000 and 2000 microseconds by default. max_pulse 2000 the pulse widths for the two ends of travel, 1000 and 2000 microseconds by default. range 180 degrees of travel, 180 by default. speed 600 how fast the horn moves towards a new angle, 600 degrees per second. mode positional (or continuous) rpm 110 How it is modeled ## What is true about the Hobby servo, here ### What is modeled The part is a stopwatch on one pin and a horn that walks towards the angle the stopwatch names: a rising edge starts the clock, a falling edge stops it, a width outside the min_pulse–max_pulse window is treated as noise and ignored, and with no pulses at all the horn stays exactly where it is, the way a real servo does when its signal wire falls off. speed matches the datasheet's 0.1 seconds per sixty degrees. A servo that only sweeps 120 degrees, or one that wants the Arduino library's default 544–2400 us window, is those three numbers changed and nothing else. ### Not modeled Current. A real SG90 pulls a quarter of an amp when it stalls and can brown out the board driving it (the single most common reason a servo project misbehaves on the bench), but Mokxi's supply rails have no impedance to sag, so a sag here would be a lie about something that cannot happen in this simulator. VCC/GND are read for one thing only: below 4 V the servo does not move at all. No torque, no load and no overshoot. The horn walks to its target at a constant 600 degrees a second and stops dead. There is no acceleration, no settling, no hunting around the target, no dead band (a real SG90 ignores changes under about 5 microseconds of pulse width) and no gear backlash, so a commanded angle is always reached exactly. The 0.1 seconds per sixty degrees is the datasheet's unloaded figure and applies here whatever is on the horn, because there is nothing on the horn. The stopwatch is also more forgiving than a real servo's: the horn is updated every 20 ms whatever the pulse rate is, a pulse longer than 3 ms is discarded rather than treated as a fault, and a gap in the pulse train is simply held rather than released. From Servo (hobby, SG90 style), in full. Projects ## See the Hobby servo in a project Shown here on: Arduino Uno R3 Learn ## Where it turns up in a lesson ### In a learn article - Arduino Servo Motor with a Potentiometer More parts ## The rest of the bench Every one of these is drawn and simulated the same way. Full-size breadboard A real 0.1 inch grid with the rails and the center channel, 63 columns wide. Jumper wires Drag from any pin or hole to any other. Corners snap, and you can drag them. Power A supply rail at the voltage you choose. Ground The other end of every circuit. LED Lights when current flows. Five colors, and the brightness is what your eye would see. Resistor Any value you like, with the color bands drawn to match. ESP32-C3-DevKitM-1 A RISC-V board that runs your firmware at 160 MHz on the real memory map. Pushbutton A 12 mm tactile switch. Hold it while the simulation runs. Raspberry Pi Pico The RP2040 board on our own Cortex-M0+ core. Pick a program and press Run. Raspberry Pi Pico W Raspberry Pi Pico W (RP2040). The same board and the same pinout as a Pico, with the CYW43439 on it. The WiFi is simulated (no radio, no real internet), and the on-board LED, which hangs off that chip rather than off GP25, is driven through the same path. Everything else is the Pico. STM32F411 Black Pill The Black Pill on our own Cortex-M4 core. Pick a program and press Run. BBC micro:bit V2 The nRF52833 board with its 5x5 LED matrix, buttons A and B and a speaker. Wire the rings to a breadboard. See every part ## Wire up the Hobby servo Open the editor and push it into the breadboard. It is free, and it runs on your own machine. Start building Open the editor