Item Name: SG90 Mini Servo
Operating Speed (4.8V no load): 0.1sec/180 degrees
Stall torque: 1.2kg / 1.4kg/cm(4.8V)
operating voltage: 4.8V-6V
Temperature range: -30℃~60℃
Dead band width: 7us
Item size: 30 x 22x 11mm
Item weight: about 9g
Connector wire length: 24cm

Micro Servo Motor SG90 Tower Pro Features:

Control Specification?
Control system: Change the pulse width
Amplifier type: Analog controller
Operating trave:l120°±10° (900?2100 ?sec)
Left & Right travelling Angle deviation:? 6°
Centering deviation:? 1°
Neutral position:1500 ?sec
Dead band width:7 ?sec
Rotating direction: Counter Clockwise (900?2100?sec)
Pulse width range:900?2100 ?sec
Maximum travel: About 120° (900?2100 ?sec)
High quality and high cost performance.
All Nylon Gear.
240mm connector wire.
Large stall torque of 1.4 Kg.
Small size and light weight.
With 3 sets of servo horns and fittings.

A servomotor is a closed-loop servomechanism that uses position feedback to control its motion and final position. The input to its control is a signal (either analog or digital) representing the position commanded for the output shaft.

The motor is paired with some type of position encoder to provide position and speed feedback. In the simplest case, only the position is measured. The measured position of the output is compared to the command position, the external input to the controller. If the output position differs from that required, an error signal is generated which then causes the motor to rotate in either direction, as needed to bring the output shaft to the appropriate position. As the positions approach, the error signal reduces to zero, and the motor stops.

en.wikipedia.org