Engineering Glossary: L
48 definitions in plain language.
48 terms beginning with L. Use the filter to narrow the list, or the letters to jump to another part of the glossary.
48 terms
- L10 life #
- The number of revolutions that 90 percent of a group of identical bearings survive; the standard rating life. Mechanical design and mechanics Read more: Bearing Life (L10) Calculator
- Ladder logic #
- A PLC programming language drawn like relay circuit diagrams, with contacts and coils on rungs. Automation, controls and robotics Read more: Ladder Logic Simulator
- Laminar flow #
- Smooth, orderly flow in layers, found at low Reynolds numbers. Fluids, heat and thermodynamics Read more: Pipe Friction and the Moody Diagram
- Laplace transform #
- A mathematical tool that turns differential equations into algebra, used to analyze control systems. Automation, controls and robotics
- Laser safety class #
- A rating of the hazard of a laser, from Class 1 (safe) to Class 4 (dangerous to eyes and skin). Math, units, quality and workshop
- Latency #
- The delay between sending and receiving a message. Automation, controls and robotics
- Latency (computing) #
- The delay between a request and its response. Programming, data and computing
- Latent heat #
- The heat absorbed or released when a substance changes phase at constant temperature, such as melting or boiling. Fluids, heat and thermodynamics
- Layer height #
- The thickness of each layer in a 3D print; thinner layers give a smoother surface and take longer. Materials, manufacturing and measurement
- Lead-free solder #
- Solder without lead, such as tin-silver-copper alloys, with a higher melting point than tin-lead. Electronics
- Lead screw #
- A threaded rod that turns rotation into straight-line motion. Mechanical design and mechanics Read more: Power Screws and Lead Screws
- Lead time #
- The time between placing an order and receiving it. Math, units, quality and workshop
- Leaf spring #
- A flat curved strip of spring steel, used in vehicle suspensions. Mechanical design and mechanics
- Lean manufacturing #
- An approach that aims to remove waste from a production process. Math, units, quality and workshop
- Least material condition #
- The condition in which a feature contains the least material, such as the largest hole. Materials, manufacturing and measurement
- Least squares #
- A method of fitting a curve by minimizing the sum of the squares of the differences from the data. Programming, data and computing
- LED #
- Light-emitting diode: a diode that gives off light when current flows through it. Electronics Read more: Voltage Divider and LED Resistor Calculator
- Level sensor #
- A sensor that measures the height of liquid or solids in a tank. Automation, controls and robotics
- Library #
- A collection of ready-made code that programs can use. Programming, data and computing
- Life-cycle cost #
- The total cost of a product over its whole life, including purchase, running, maintenance and disposal. Math, units, quality and workshop
- Lift #
- The force on a body perpendicular to the flow, such as that on an aircraft wing. Fluids, heat and thermodynamics
- Light curtain #
- A safety sensor with beams of light that stops a machine when a person breaks the beams. Automation, controls and robotics Read more: Safety Sensors and Devices
- Limit dimensions #
- The largest and smallest sizes permitted for a feature. Materials, manufacturing and measurement
- Limit switch #
- A switch operated by the moving part of a machine to mark the end of travel. Automation, controls and robotics
- Linear regression #
- Fitting a straight line (or plane) to data by least squares. Programming, data and computing
- Linear regulator #
- A voltage regulator that drops the excess voltage as heat; simple and quiet. Electronics Read more: LM317 Adjustable Regulator Calculator
- Line voltage #
- The voltage between two phase conductors of a three-phase system. Electrical power and machines
- Linker #
- A program that combines compiled pieces of code into one executable. Programming, data and computing
- Linux #
- A free, open-source operating system widely used in servers and embedded devices. Programming, data and computing
- Lithium-ion #
- A rechargeable battery chemistry with high energy density, widely used in electronics and vehicles. Electrical power and machines
- LMTD #
- Log mean temperature difference: the average driving temperature difference in a heat exchanger. Fluids, heat and thermodynamics
- Load #
- The device or equipment that uses electrical power; also the power it draws. Electrical power and machines
- Load cell #
- A transducer that measures force or weight, usually with strain gauges. Automation, controls and robotics
- Load path #
- The route that a force takes through a structure from where it is applied to where it is supported. Mechanical design and mechanics
- Locked-rotor current #
- The large current a motor draws at start, with the shaft not yet turning; typically six times the full-load current. Electrical power and machines
- Lockout #
- A safety method that isolates and locks an energy source before work on equipment. Math, units, quality and workshop
- Lockout tagout #
- A safety procedure that locks and labels switches in the off position so equipment cannot be energized during work. Electrical power and machines Read more: Electrical Safety, Testing and Troubleshooting
- Logarithm #
- The power to which a base must be raised to give a number; used for decibels, pH and wide-ranging data. Math, units, quality and workshop
- Logic analyzer #
- An instrument that records many digital signals at once and shows their timing. Electronics
- Logic gate #
- A circuit that performs a basic logic function such as AND, OR or NOT. Electronics Read more: Digital Electronics and Microcontrollers
- Logic level #
- The voltage range that represents a 0 or 1 in a digital circuit, such as 0 V and 3.3 V. Electronics
- Logic level shifter #
- A circuit that converts digital signals between different voltage levels, such as 3.3 V and 5 V. Programming, data and computing
- Loop #
- A part of a program that repeats until a condition is met. Programming, data and computing
- Loss coefficient #
- A number K that multiplies the velocity head to give the pressure loss in a fitting. Fluids, heat and thermodynamics
- Low-pass filter #
- A filter that passes low frequencies and attenuates high ones. Electronics
- Low-power mode #
- A state in which a microcontroller turns off parts of the chip to save battery. Programming, data and computing
- Lubricant #
- A substance placed between moving surfaces to reduce friction and wear. Math, units, quality and workshop Read more: Lubrication, Wear and Gear Failures
- LVDT #
- Linear variable differential transformer: a sensor that measures small straight-line displacement. Automation, controls and robotics