Engineering Glossary: E
49 definitions in plain language.
49 terms beginning with E. Use the filter to narrow the list, or the letters to jump to another part of the glossary.
49 terms
- Earth fault loop impedance #
- The impedance of the path a fault current takes through the live conductor and earth back to the source; it decides how fast protection trips. Electrical power and machines
- Earthing #
- Connecting parts of an installation to the general mass of earth for safety. Also called grounding. Electrical power and machines
- Eccentricity #
- The offset of a load or an axis from the center line. Mechanical design and mechanics
- Edge computing #
- Processing data near where it is produced, instead of sending it to a distant data center. Programming, data and computing
- EDM #
- Electrical discharge machining: removing material with sparks between an electrode and a conductive workpiece. Materials, manufacturing and measurement
- EEPROM #
- Non-volatile memory that can be erased and rewritten byte by byte, used for settings. Programming, data and computing
- Efficiency #
- The ratio of useful output power to input power, always less than 1 for real machines. Mechanical design and mechanics
- Eigenvalue #
- A number such that multiplying a matrix by a certain vector gives that vector scaled by the number; in vibration it gives natural frequencies. Math, units, quality and workshop
- Elastic collision #
- A collision in which kinetic energy is conserved. Math, units, quality and workshop
- Elastic limit #
- The largest stress a material can take and still return to its original shape when the load is removed. Mechanical design and mechanics
- Elastomer #
- A rubber-like material that can stretch a long way and return to its shape. Materials, manufacturing and measurement
- Elastomer hardness #
- The stiffness of a rubber, measured on the Shore A scale; common O-rings are 70 Shore A. Math, units, quality and workshop
- Electrolytic capacitor #
- A polarized capacitor with high capacitance in a small size, used in power supplies. Electronics
- Electroplating #
- Coating a part with a thin layer of metal by electrolysis, such as zinc, nickel or chrome. Materials, manufacturing and measurement
- Embedded system #
- A computer built into a device to control it, such as in a washing machine or a car engine. Programming, data and computing
- EMC #
- Electromagnetic compatibility: the ability of equipment to work without causing or suffering interference. Electronics Read more: EMC and Noise at Board Level
- Emergency stop #
- A manually operated device that stops a machine quickly in an emergency. Automation, controls and robotics
- EMI #
- Electromagnetic interference: unwanted electrical noise that affects a circuit. Electronics
- Emissivity #
- The ratio of the heat a surface radiates to that of a perfect black body at the same temperature. Fluids, heat and thermodynamics
- Encoder #
- A sensor that gives pulses or a code as a shaft turns, measuring position and speed. Automation, controls and robotics Read more: Position, Displacement and Speed Sensors
- Encryption #
- Scrambling data so that only someone with the key can read it. Programming, data and computing
- End effector #
- The tool at the end of a robot arm, such as a gripper or a welding torch. Also called end-of-arm tooling. Automation, controls and robotics
- Endianness #
- The order in which the bytes of a multi-byte number are stored: big-endian puts the most significant byte first. Programming, data and computing
- Endurance limit #
- The stress amplitude below which a material survives an unlimited number of cycles, found in steels but not in aluminum. Mechanical design and mechanics
- Energy #
- The capacity to do work, measured in joules. Mechanical design and mechanics
- Engineering economics #
- The study of costs and benefits used to choose between engineering alternatives. Math, units, quality and workshop Read more: Engineering Fundamentals
- Enthalpy #
- The sum of a system's internal energy and the product of its pressure and volume; used for flow processes. Fluids, heat and thermodynamics
- Enthalpy of air #
- The total heat content of moist air per unit mass of dry air, used for cooling and heating loads. Fluids, heat and thermodynamics
- Entropy #
- A measure of the disorder of a system, and of how much energy is unavailable for work. Fluids, heat and thermodynamics
- Equilibrium #
- The state in which the sum of all forces and the sum of all moments on a body are zero. Mechanical design and mechanics
- Equivalent length #
- The length of straight pipe that gives the same pressure loss as a fitting. Fluids, heat and thermodynamics
- Ergonomics #
- The design of tools, equipment and tasks to fit the people who use them. Math, units, quality and workshop
- Error (control) #
- The difference between the setpoint and the process variable. Automation, controls and robotics
- Error propagation #
- Working out the uncertainty of a calculated result from the uncertainties of the measurements that go into it. Math, units, quality and workshop
- ESD #
- Electrostatic discharge: a sudden transfer of static charge that can damage electronic parts. Electronics
- ESP32 #
- A low-cost microcontroller with built-in Wi-Fi and Bluetooth. Programming, data and computing
- ESR #
- Equivalent series resistance: the small resistance in series with a real capacitor that causes heating and ripple. Electronics
- Ethernet #
- A family of wired network standards, now common in industry. Automation, controls and robotics
- Euler buckling load #
- The compressive load at which a long slender column buckles: π² E I ÷ (K L)². Mechanical design and mechanics
- Euler method #
- The simplest way to solve a differential equation numerically, by stepping forward along the slope. Math, units, quality and workshop
- Evaporator #
- A heat exchanger in which a liquid boils and absorbs heat. Fluids, heat and thermodynamics
- Excess air #
- The air supplied above the stoichiometric amount, to ensure complete combustion. Fluids, heat and thermodynamics
- Exponential function #
- A function in which the variable is in the exponent, describing growth or decay such as ex. Math, units, quality and workshop
- Exposure limit #
- The maximum amount or time of exposure to a hazard, such as noise or a chemical, that is considered acceptable. Math, units, quality and workshop
- Extension spring #
- A helical spring that resists being stretched, with hooks at the ends. Mechanical design and mechanics
- Extinguisher class #
- The type of fire an extinguisher is made for: A for ordinary combustibles, B for flammable liquids, C for electrical and D for metals. Math, units, quality and workshop
- Extrapolation #
- Estimating a value outside the range of the known data points, less reliable than interpolation. Programming, data and computing
- Extrusion #
- Forcing material through a shaped die to make a long part with a constant cross-section. Materials, manufacturing and measurement
- Extrusion (seal) #
- The squeezing of a seal into the clearance gap under high pressure. Math, units, quality and workshop