Electronic speed controlAn electronic speed control (ESC) is an electronic circuit that controls and regulates the speed of an electric motor. It may also provide reversing of the motor and dynamic braking. Miniature electronic speed controls are used in electrically powered radio controlled models. Full-size electric vehicles also have systems to control the speed of their drive motors. An electronic speed control follows a speed reference signal (derived from a throttle lever, joystick, or other manual input) and varies the switching rate of a network of field effect transistors (FETs).
Upper limbThe upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulder, elbow, wrist and knuckle joints. In humans, each upper limb is divided into the arm, forearm and hand, and is primarily used for climbing, lifting and manipulating objects. In formal usage, the term "arm" only refers to the structures from the shoulder to the elbow, explicitly excluding the forearm, and thus "upper limb" and "arm" are not synonymous.
Radio-controlled modelA radio-controlled model (or RC model) is a model that is steerable with the use of radio control. All types of model vehicles have had RC systems installed in them, including ground vehicles, boats, planes, helicopters and even submarines and scale railway locomotives. Radio control has been around since Nikola Tesla demonstrated a remote control boat in 1898. World War II saw increased development in radio control technology. The Luftwaffe used controllable winged bombs for targeting Allied ships.
CrampA cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the affected muscle. A cramp usually goes away on its own over a period of several seconds or (sometimes) minutes. Cramps are common and tend to occur at rest, usually at night (nocturnal leg cramps).
