Skip to content
motors / sg90-servo.md

SG90 9g Servo

The hobby standard 9-gram servo. 180° rotation (some clones are 270°), plastic gears, 4.8 V nominal. PWM-controlled — 1 ms = full left, 1.5 ms = center, 2 ms = full right, 20 ms frame.

In stock Tower Pro

Specs

Spec Value
Voltage 4.8 – 6 V
Stall torque 1.8 kg·cm @ 4.8 V
Stall current ~550 mA
Rotation ~180°
Speed 0.1 s / 60° @ 4.8 V
Weight 9 g
Wire colors brown = GND, red = V+, orange/yellow = signal

Wiring (Arduino Uno)

SG90 Arduino
Brown (–) GND
Red (+) 5 V (small loads only) — for stall use a separate 5 V/2 A supply
Orange / Yellow D9 (any PWM-capable digital pin)

Brown-out

The Uno's onboard 5 V regulator can deliver maybe 500 mA. One SG90 can pull 550 mA at stall — that crashes the MCU. Power servos from a separate 5 V supply and tie the grounds together.

Code

#include <Servo.h>
Servo s;

void setup() { s.attach(9); }

void loop() {
  for (int a = 0; a <= 180; a++) { s.write(a); delay(15); }
  for (int a = 180; a >= 0; a--) { s.write(a); delay(15); }
}

Schematic

SG90 internals = small DC motor + plastic gears + analog control PCB (potentiometer feedback + comparator). Not a user-serviceable part — see servodatabase.com for the spec sheet.

Last updated: 2026-05-13 · Source on GitHub