Engineering Glossary: F

61 definitions in plain language.

61 terms beginning with F. Use the filter to narrow the list, or the letters to jump to another part of the glossary.

61 terms
Factory acceptance test #
A test of a system at the builder's site before it is shipped to the customer. Also called FAT. Automation, controls and robotics
Failure rate #
The number of failures per unit of time, often shown as failures per million hours. Math, units, quality and workshop
Farad #
The SI unit of capacitance: one coulomb per volt. Electrical power and machines
Fatigue #
Failure of a part under repeated loading at stresses well below its static strength. Mechanical design and mechanics
Fatigue strength #
The stress amplitude a material can withstand for a stated number of cycles, such as one million. Mechanical design and mechanics
Fault level #
The maximum short-circuit current or power available at a point in an electrical system. Electrical power and machines
FDM #
Fused deposition modeling: 3D printing by extruding melted plastic filament through a nozzle. Materials, manufacturing and measurement
Feature #
A measurable property of the data used as an input to a model. Programming, data and computing
Feature control frame #
The rectangle on a drawing that states a geometric tolerance, its value and its datum references. Materials, manufacturing and measurement
Feedforward #
Control that uses a measured disturbance to correct the output before the error appears. Automation, controls and robotics
Feed rate #
How fast the cutter or workpiece advances, in mm/min or inches per minute. Materials, manufacturing and measurement
Ferrite #
A soft, magnetic form of iron (body-centered cubic) with very little dissolved carbon. Materials, manufacturing and measurement
Ferrite bead #
A small ferrite component that absorbs high-frequency noise on a wire. Electronics
Ferrous metal #
A metal based on iron, such as steel and cast iron. Materials, manufacturing and measurement
Fiberglass #
A composite of glass fibers in a plastic resin. Materials, manufacturing and measurement
Fieldbus #
A digital network that connects field devices to a controller over a single cable. Automation, controls and robotics
Fillet radius #
The rounded transition at an inside corner, which reduces stress concentration. Mechanical design and mechanics
Fillet weld #
A triangular weld joining two surfaces at right angles. Mechanical design and mechanics Read more: Fillet Weld Size and Strength Calculator
Filter #
A circuit that passes some frequencies and blocks others. Electronics Read more: RC Time Constant and Filter Calculator
Filter (fluid) #
A device that removes particles from a fluid. Fluids, heat and thermodynamics
Fin #
An extended surface that adds area to increase heat transfer, as on a heat sink or engine cylinder. Fluids, heat and thermodynamics Read more: Heat Transfer
Finite element analysis #
A numerical method that divides a part into small elements to calculate stress, heat flow and other effects. Also called FEA. Programming, data and computing
Fire triangle #
The three things a fire needs: fuel, oxygen and heat. Math, units, quality and workshop
Firewall #
A device or software that allows or blocks network traffic by rules. Automation, controls and robotics
Firmware #
Software stored in a device's non-volatile memory that controls how it works. Programming, data and computing
First law of thermodynamics #
Energy is conserved: the change in a system's energy equals the heat added minus the work done. Fluids, heat and thermodynamics Read more: Thermodynamics and Steam
Fit #
The relationship between a shaft and a hole that go together: clearance, transition or interference. Materials, manufacturing and measurement Read more: Fit Calculator (ISO 286)
Fixed beam #
A beam whose ends are clamped so they cannot rotate. Also called built-in or encastré. Mechanical design and mechanics
Fixture #
A device that holds and locates a workpiece in a known position during machining or inspection. Materials, manufacturing and measurement
Flash #
A thin extra layer of material that escapes at the parting line of a mold. Materials, manufacturing and measurement
Flash memory #
Non-volatile memory that keeps its contents without power and is erased in blocks; holds the program in most microcontrollers. Programming, data and computing
Flatness #
A geometric tolerance that limits how far a surface may deviate from a perfect plane. Materials, manufacturing and measurement Read more: Form Tolerances
Flip-flop #
A circuit that stores one bit and changes only on a clock edge. Electronics
Floating point #
A way of storing real numbers as a mantissa and an exponent, with limited precision. Programming, data and computing Read more: Numbers and Floating Point
Flow meter #
An instrument that measures the flow rate of a fluid. Automation, controls and robotics Read more: Pressure, Level and Flow Sensors
Flow rate #
The volume or mass of fluid passing a point per unit time. Fluids, heat and thermodynamics Read more: Flow Rate Converter
Fluid #
A substance, liquid or gas, that flows and takes the shape of its container. Fluids, heat and thermodynamics
Fluid power #
The general term for hydraulic and pneumatic systems. Fluids, heat and thermodynamics
Flux #
A chemical that cleans metal surfaces and helps solder flow during soldering. Electronics
Flyback diode #
A diode across a relay or motor coil that carries the current when the coil is switched off, protecting the switch. Also called a freewheeling diode. Electronics
Flywheel #
A heavy wheel that stores rotational energy and smooths out changes in speed. Mechanical design and mechanics Read more: Flywheels, Balancing and Rotors
FMEA #
Failure mode and effects analysis: a method of listing how a product can fail, how bad it would be and how to prevent it. Math, units, quality and workshop
Footprint #
The pattern of pads on a PCB for one component. Electronics
Forging #
Shaping metal by hammering or pressing it, usually hot, which improves its grain structure and strength. Materials, manufacturing and measurement
Forward kinematics #
Finding the position of a robot tool from the joint angles. Automation, controls and robotics
Forward voltage #
The voltage drop across a conducting diode or LED: about 0.7 V for silicon. Electronics
Four-bar linkage #
A mechanism with four links joined in a loop by four pin joints. Mechanical design and mechanics
Fourier series #
A way of writing a repeating signal as a sum of sine and cosine waves. Math, units, quality and workshop
Fourier transform #
A tool that breaks a signal into its frequency components. The fast version is called the FFT. Math, units, quality and workshop
Fracture toughness #
A material's resistance to the growth of a crack, measured as KIC. Mechanical design and mechanics
Free air #
Air at atmospheric conditions, the basis for stating compressor output in scfm or L/min. Fluids, heat and thermodynamics
Free-body diagram #
A sketch of a body isolated from its surroundings, showing all the forces and moments acting on it. Mechanical design and mechanics
Frequency #
The number of cycles per second of an alternating quantity, in hertz: 50 or 60 Hz for mains power. Electrical power and machines
Friction #
The force that resists sliding between two surfaces in contact. Mechanical design and mechanics
Friction factor #
The dimensionless coefficient in the Darcy-Weisbach equation, found from the Reynolds number and relative roughness. Fluids, heat and thermodynamics
Full-load current #
The current a motor draws when delivering its rated power. Electrical power and machines Read more: Motor Full-Load Current (Three-Phase)
Function #
A named block of code that does a task and may return a value. Programming, data and computing
Function block diagram #
A PLC language in which blocks for functions are connected by lines. Automation, controls and robotics
Function generator #
An instrument that produces test waveforms such as sine, square and triangle. Electronics
Fundamental deviation #
In the ISO system, the deviation that fixes the position of the tolerance zone relative to the basic size, shown by a letter. Materials, manufacturing and measurement
Fuse #
A protective device with a wire that melts and opens the circuit when current is too high. Electrical power and machines

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