AI-3
GIMBAL—A mechanical frame, with two perpendicular, intersecting axes of rotation, used to
support and furnish a gyro wheel with the necessary freedom to tilt in any direction.
GYRO—Abbreviation for gyroscope.
GYROSCOPE—A mechanical device containing a spinning mass mounted so that it can assume
any position in space.
IC SYNCHROS—Electromechanical devices, used to transmit information, that operate on the
same principles of interacting magnetic fields as synchros, but differ in their direction of
rotation and the amount of torque obtainable. Because of their construction, they are
sometimes called reversed synchros.
INERTIA—The physical tendency of a body in motion to remain in motion and a body at rest to
remain at rest unless acted upon by an outside force (Newton's First Law of Motion).
MAGNETIC AMPLIFIER—An electromagnetic device that uses one or more saturable
reactors to obtain a large power gain. This device is used in servo systems requiring large
amounts of power to move heavy loads.
MILITARY STANDARD SYNCHROS—Synchros that conform to specifications that are
uniform throughout the Armed Services.
MODULATOR—A circuit used in servo systems to convert a dc signal to an ac signal. The
output ac signal is a sine wave at the frequency of the ac reference voltage. The amplitude of
the output is directly related to the amplitude of the dc input. The circuit's function is
opposite to that of a DEMODULATOR.
MULTI-LOOP SERVO SYSTEM—A servo system that contains more than one servo loop,
each loop designed to perform its own function.
MULTISPEED SYNCHRO SYSTEMS—Systems that transmit data at different transmission
speeds; for example, dual-speed and tri-speed synchro systems.
NEWTON’S SECOND LAW OF MOTION—If an unbalanced outside force acts on a body,
the resulting acceleration is directly proportional to the magnitude of the force, is in the
direction of the force, and is inversely proportional to the mass of the body.
POSITION SENSOR—A component in a servo system that measures position and converts the
measurement into a form convenient for transmission as a feedback signal.
POSITION SERVO SYSTEM—A servo system whose end function is to control the position of
the load it is driving.
POTENTIOMETER—An electromechanical device, used as a position sensor in servo systems,
having a terminal connected to each end of a restrictive element, and a third connected to a
wiper contact. The output is a voltage that is variable depending upon the position of the
wiper contact. The potentiometer is commonly referred to as a variable voltage divider. It, in
effect, converts mechanical information into an electrical signal.
PRECESSION—The rotation of the spin axis of a gyro in response to an applied force. The
direction of precession is always perpendicular to the direction of applied force.
