Soldering Iron Selection Calculator

Iron specs from project type and components.

Stall Torque (kg·cm)

Operating Voltage (V)

Number of Servos

Duty Cycle (%)

Speed (sec/60°)

Tab to move between fields

Total Stall Current (mA)

Avg Operating Current (mA)

10.8

Idle Current (mA)10

Stall Power (W)0.45

Avg Operating Power (W)0.05

Min PSU Current (A)0.11

Angular Speed (°/sec)400

Runtime (2000mAh, hrs)185.2

Idle Power W0.05

Mech Power W0.57

How to Use This Calculator

Enter the stall torque (kg·cm) and operating voltage (V) for your servo motor.
Set the number of servos and expected duty cycle (%) for your application.
Enter speed (sec/60°) to characterize performance.
Review stall current (mA), average operating current, idle current, and power consumption (W).
Use these values to correctly size your power supply for the servo system.

How the result changes with Operating Voltage (V)

Stall Torque (kg·cm): Servo stall torque from datasheet (e.g. SG90: 1.8, MG996R: 11).
Operating Voltage (V): Supply voltage to servo (typical: 4.8V or 6V; never exceed max rated).
Number of Servos: Total number of servos powered simultaneously.
Duty Cycle (%): Percentage of time servos are actively moving (not holding). 30% is typical for robotic arms.
Speed (sec/60°): Time for 60-degree rotation from datasheet (e.g. SG90: 0.12s, MG996R: 0.15s).

Total Stall Current (mA): Maximum current draw when all servos are stalled (worst case for PSU sizing).
Avg Operating Current (mA): Average current during normal operation accounting for duty cycle.
Idle Current (mA): Current when servos hold position but don't move.
Stall Power (W): Peak power consumption at stall.
Avg Operating Power (W): Average power during normal operation.
Min PSU Current (A): Minimum power supply current rating (includes 20% safety margin).
Angular Speed (°/sec): Servo rotation speed in degrees per second.
Runtime (2000mAh, hrs): Estimated runtime on a 2000mAh battery pack.

Identify Input Parameters
4 parameters
Stall Torque (kg·cm) = 2.5, Operating Voltage (V) = 5, Number of Servos = 1, Duty Cycle (%) = 30 = 5 input(s) provided
Calculate Total Stall Current
Total Stall Current = stallCurrentPerServo * servoCount
90 = 90
Calculate Avg Operating Current
Avg Operating Current = operatingCurrentPerServo * servoCount * (dutyCyclePct / 100)
10.8 = 10.8
Calculate Idle Current
Idle Current = idleCurrentPerServo * servoCount
10 = 10
Calculate Stall Power
Stall Power = (stallCurrentMa / 1000) * operatingVoltage
0.45 = 0.45