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Fiberglass-reinforced Plastic (FRP)

A plastic structure or panel that is reinforced with fiberglass.

FICD

Fast idle control device.

Field

1. Generally, any area being affected by some physical force such as 2. Electrical force in the space around electrically charged particles. 3. The lines of force in a natural or man-made magnet between its north and south poles.

Field Coil

The coil, or winding, around the field magnets or pole pieces of a motor or generator. Also known as field winding.

Field Density

The density of the magnetic field, measured in the number of lines of force per unit area, dependent upon the strength of the field element, the number of turns of wire, and the size and characteristics of the pole piece.

Field Effect Transistor

A unipolar transistor in which current flow is controlled by voltage in a capacitance field.

Field Relay

A relay that connects the alternator to the battery when alternator voltage is greater than battery voltage and disconnects it when battery voltage is greater than alternator voltage.

Field Terminal

The electrical terminal connecting the field coil to the voltage regulator.

Field Winding

A term often used for field coil.

Field-effect Transistor (FET)

A 3-terminal semiconductor device where current flows from source to drain due to a conducting channel formed by a voltage field between the gate and the source.

Field-frame Assembly

The round, soft iron frame of a generator or motor into which the field coils are assembled.

Fifth Wheel

A coupling device mounted on a truck, and used to connect a semi-trailer. It acts as a hinge point to allow changes in direction of travel between the tractor and semi-trailer.

Fifth-wheel Accessories

Products designed to work with--or around--a fifth-wheel hitch in a pickup truck. This includes special air gates with a cutout for trailer clearance and special tool boxes, including fifth-wheel boxes and RV chests.

Fifth-wheel Height

1. The distance from the ground to the top of the fifth wheel when it is level and parallel with the ground. 2. The height from the tractor frame to the top of the fifth wheel, as applies to data given in fifth-wheel literature.

Fifth-wheel Hitch

A hitch having a slotted wheel-shaped plate on a tow vehicle into which the kingpin of a fifth-wheel trailer locks to connect the trailer to the vehicle.

Fifth-wheel Hitch

Similar to (but much smaller than) the hookups used by 18-wheelers. Commonly is used to tow an RV or a large horse trailer or other enclosed trailer. A fifth-wheel hitch must be installed in the back of a pickup truck, either mounted in the bed or on a flatbed, right above the truck's rear end. Hooking the trailer to the vehicle in this manner offers improved stability and ease of turning and maneuvering, as well as the ability to tow substantially more weight than is possible with a ball-variety weight-carrying hitch or weight-distributing hitch. Since the fifth-wheel hookup does interfere with bed space and the tailgate, companies have developed a number of fifth-wheel accessories to solve these and other problems.

Fifth-wheel Hookup

See fifth-wheel hitch.

Fifth-wheel Top Plate

The portion of the fifth-wheel assembly that contacts the trailer bolster plate and houses the licking mechanism that connects to the kingpin.

Filament

The heated element in an incandescent lamp or vacuum tube.

File

1. A hand tool with fine teeth for removing small amounts of material. 2. A collection of records treated as a basic unit of storage.