A geared motor consists of a regular direct current (DC) motor and a gearbox. The ratio of the gears is usually given in the datasheet if you look up the type number. Using gears decreases the speed of rotation but increases the available torque.
To change the direction of rotation, simply change the polarity of the power supply, or use a so called H-bridge motor driver.
A DC motor has a maximum supply voltage. you can change the the speed of the motor by means op a PWM (Pulse width Modulation) signal.
Typical applications: toys, battery operated power drills, toothbrushes.
- Motor supply voltage and current.
- Gear ratio, as it is determining the Rotations Per Minute (RPM) of the outgoing motor shaft.
- Diameter and shape of the motor shaft, as it needs to connect to other wheels, shafts, or gears.
- Maximum torque.