Glossary · 177 terms
The hardware glossary for founders.
EVT, NRE, FCC Part 15, FOC, AQL — what they mean, why they matter for your product, and where they bite.
No match — .
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ADC and DAC Converters between the analog world and firmware: an ADC turns a voltage into a number; a DAC turns a number into a voltage. embedded AI agent A system in which a language model plans and carries out multi-step tasks by calling tools, such as searches, databases or device APIs, to reach a goal. ai Anomaly detection Automatically flagging data that departs from normal behavior, such as unusual vibration or energy use, to catch faults before they become failures. ai Antenna design and matching Choosing, placing and tuning an antenna so a wireless product achieves its expected range inside its real enclosure, near hands, batteries and metal. electrical Approved vendor list (AVL/AML) The list of manufacturers and part numbers approved for each line of the BOM, so buyers and factories know exactly which substitutes are allowed. electrical AQL (acceptance quality limit) A statistical sampling system for accepting or rejecting a production lot by inspecting a sample; the AQL is the worst average defect rate accepted. manufacturing
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BACnet The open building-automation protocol, published as ANSI/ASHRAE Standard 135 and ISO 16484-5, used by HVAC and other building controllers. hvac Battery management system (BMS) The electronics that keep a battery pack safe: monitoring cell voltages, current and temperature, balancing cells, and disconnecting on faults. power Bed-of-nails fixture A test fixture with an array of spring-loaded pins that touch test points on a circuit board all at once, used for in-circuit testing and programming. manufacturing Bill of materials (BOM) The complete list of every part, quantity and approved source needed to build a product; it drives purchasing, cost and manufacturing. electrical Bluetooth Low Energy (BLE) A short-range 2.4 GHz wireless standard designed for low power, used to connect devices to phones and to each other. embedded Boost converter A switching power supply that raises a DC voltage, for example from one battery cell to 5 V, for circuits that need more than the source provides. power Bootloader (and secure boot) The small program that runs first at power-up, checks and starts the main firmware and handles updates; secure boot adds signature checks. embedded Brushless DC motor (BLDC) An electric motor with permanent magnets and electronic commutation instead of brushes: long life, high efficiency and compact power, but it needs a driver. controls BTU (and tons of cooling) A unit of heat energy: the heat needed to raise one pound of water by 1 °F. HVAC capacity is quoted in Btu per hour; 12,000 Btu/h is one "ton" of cooling. hvac Buck converter A switching power supply that efficiently steps a higher DC voltage down to a lower one, such as 12 V to 3.3 V, by switching rapidly and filtering the result. power Building automation system (BAS/BMS) The controllers, sensors and software that run a commercial building's HVAC, lighting and other systems, with central monitoring and alarms. hvac
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C-rate Charge or discharge current expressed relative to capacity: 1C fully discharges a battery in about an hour, 0.5C in about two hours, 2C in about 30 minutes. power California Proposition 65 California law requiring clear warnings before exposing people to listed chemicals that cause cancer or reproductive harm; it affects many consumer products. certification CAN bus A robust two-wire network built for vehicles and machines, letting many controllers share prioritized messages reliably in electrically noisy environments. embedded CC/CV charging The standard lithium-ion charging method: constant current until the cell reaches its maximum voltage, then constant voltage while the current tapers off. power CE marking The manufacturer's declaration that a product meets all applicable EU product laws; required to sell many product types in the European Economic Area. certification Channel margin (retail and distribution) The share of the retail price kept by distributors and retailers; selling through channels means you earn the wholesale price, not the shelf price. business CNC machining Cutting parts from solid metal or plastic with computer-controlled tools; ideal for prototypes and low volumes, but costly per part at high volume. mechanical Coefficient of performance (COP) Heat moved divided by energy used: a heat pump with a COP of 3 delivers three units of heat per unit of electricity, while resistance heating has a COP of 1. hvac COGS (cost of goods sold) The direct cost of producing the units you sold: materials, manufacturing labor, test, packaging, freight and duties. It is much more than the BOM alone. business Component obsolescence (EOL) When a manufacturer discontinues a part your product uses; you get a notice and a last-time-buy window, then must stockpile, find an alternate or redesign. electrical Computational fluid dynamics (CFD) Simulation of air and liquid flow and heat transfer, used to design cooling, fans, ducts and HVAC airflow and to predict pressure drop before building. mechanical Computer vision Using cameras and algorithms, increasingly neural networks, to detect, measure, classify or inspect objects, from factory checks to products that see. ai Contract manufacturer (CM / EMS) A company that builds your product to your design and specifications; EMS providers specialize in electronics assembly, often with box build and test. manufacturing Control loop rate How often a digital controller reads sensors and updates its output; it must be fast relative to the dynamics or performance and stability suffer. controls Controlled impedance Designing PCB traces to a specified characteristic impedance so fast signals such as USB, Ethernet and RF arrive cleanly without reflections. electrical CPSIA (children's products) US law requiring children's products (for ages 12 and under) to be tested by a CPSC-accepted third-party lab and certified, with strict lead and other limits. certification Creepage and clearance Minimum spacing between conductors at different voltages, through air (clearance) and along surfaces (creepage), set by safety standards. electrical Crowdfunding and pre-order fulfilment Delivering hardware promised to backers or pre-order buyers; the hard part is usually manufacturing, certification and shipping, not the campaign. business
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Dashboard A screen that summarizes live and historical data from devices or systems so people can see status, spot problems and act quickly. software Deadband (and hysteresis) A range around the setpoint where the controller deliberately does nothing, preventing rapid on-off cycling and unnecessary actuator wear. controls Decoupling capacitor Small capacitors placed right next to a chip's power pins to supply sudden current demands and keep the local supply voltage clean. electrical Design for cost (DFC) Making cost a design requirement from the start: setting a target COGS, then making architecture, part and process choices to meet it. business Design for manufacturing and assembly (DFM/DFA) Designing parts and assemblies around how they will actually be made and put together, to cut cost, defects and assembly time before tooling is made. mechanical Design for test (DFT) Designing a product so every unit can be tested quickly and thoroughly in production, with test points, debug access and self-test functions built in. electrical Device fleet management The systems and processes for identifying, provisioning, monitoring, updating and retiring every connected device a company has shipped. software DFM and DFA for PCBs Designing a circuit board to be fabricated and assembled reliably at volume, within the factory's standard capabilities and with available parts. electrical Digital twin A software model of a physical product, system or building kept in step with real data, used to simulate, monitor, predict and optimize its behavior. software Direct memory access (DMA) A hardware feature that moves data between peripherals and memory without the processor, freeing it for other work and reducing power. embedded Draft angle A slight taper on the walls of molded or cast parts so they release cleanly from the mold; missing draft causes scuffing, sticking and tooling problems. mechanical DVT (design validation test) The build stage where units made with production-intent tooling and processes are tested exhaustively for reliability, compliance and environmental performance. manufacturing
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Edge vs cloud computing Choosing where computing runs: on or near the device (edge) for speed, privacy and offline use, or in data centers (cloud) for scale and fleet analysis. software Electrostatic discharge (ESD) The sudden discharge of static electricity from a person or object into a device, which can reset, damage or destroy electronics that aren't designed for it. electrical Embeddings Numeric vectors that represent the meaning of text, images or signals so similar items sit close together; the basis of semantic search and RAG. ai EMC Directive The EU directive (2014/30/EU) requiring electrical and electronic equipment to limit its electromagnetic emissions and tolerate typical interference. certification EMI and EMC EMC means a device neither emits too much electromagnetic noise (EMI) nor malfunctions when exposed to it; most markets require testing to show both. electrical Encoder (incremental vs absolute) A position sensor; incremental encoders count steps from a reference point, absolute encoders report true position even right after power-up. controls Engineering change order (ECO) The formal process for approving, documenting and rolling out a design change to a released product, so factories, inventory and records stay in sync. manufacturing ERV and HRV (balanced ventilation) Ventilation units that bring in fresh outdoor air while recovering heat (HRV) or heat and moisture (ERV) from the outgoing stale air, to save energy. hvac EU Cyber Resilience Act (CRA) EU law setting mandatory cybersecurity rules for products with digital elements; reporting duties start September 2026, most others December 2027. certification EV charging levels and connectors US EV charging is grouped into Level 1 (120 V AC), Level 2 (208/240 V AC) and DC fast charging, using connectors such as SAE J1772, CCS and SAE J3400. power EVSE (EV charging equipment) Electric vehicle supply equipment: the charging-station hardware that safely delivers power to an EV, talks to the vehicle and often joins a network. power EVT (engineering validation test) The first build of production-intent design, used to prove the engineering works: does the product meet its functional and performance requirements? manufacturing
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FCC Part 15 US rules on radio-frequency emissions from electronics: Subpart B for unintentional radiators, Subpart C for intentional ones such as Wi-Fi and BLE. certification FDA medical device classes The US risk classes for medical devices: Class I is lowest risk, most Class II need 510(k) clearance, Class III generally needs premarket approval. certification Feedback control (closed loop) Measuring what a system is actually doing and continuously correcting the input so the output tracks a target, instead of acting blind. controls Feedforward control Acting on a known disturbance or planned change before it shows up as error, usually layered on top of feedback to make response faster and smoother. controls Field-oriented control (FOC) A motor-control technique that regulates torque and magnetic field of AC and brushless motors independently, giving smooth, efficient, quiet operation. controls Finite element analysis (FEA) Simulation that predicts stress, deflection, vibration and heat flow in parts by dividing them into small elements, guiding design before testing. mechanical First article inspection (FAI) A detailed measurement of the first parts from a new tool or process against every drawing requirement, before production is approved. manufacturing Functional circuit test (FCT) Powering up a board or finished product and checking it actually works, such as sensors reading correctly and radios connecting, before it ships. manufacturing
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Gain and phase margin Measures of how much extra gain or delay a feedback loop can tolerate before it starts to oscillate; a loop with small margins is fragile. controls GD&T (geometric dimensioning and tolerancing) A standardized symbolic language on engineering drawings that defines allowed variation in form, orientation and location relative to datums, not just size. mechanical Golden sample A unit formally approved as the reference for how the product must look, feel and perform; production units are compared against it. manufacturing Gross margin Revenue minus cost of goods sold, as a percentage of revenue; it shows how much each sale leaves to pay for engineering, marketing, overhead and profit. business
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Hardware-in-the-loop (HIL) testing Testing real controller hardware and firmware against a simulated plant in real time, so risky, rare or costly conditions can be exercised safely. controls Heat pump A machine that moves heat from one place to another with a refrigerant cycle, providing both heating and cooling far more efficiently than resistance heat. hvac HMI (human-machine interface) The screens, buttons and displays through which operators monitor and control a machine or process; good HMI design reduces errors and response time. software HS/HTS code and import duties The tariff classification number that identifies a product at customs and sets its import duty rate; the first six digits are harmonized internationally. manufacturing HVAC zoning Dividing a building into areas with separate thermostats and controlled airflow or water flow, so each zone is heated or cooled only when it needs it. hvac Hydronic heating and cooling Systems that move heat with water or a water-glycol mix through pipes to radiators, radiant floors or fan coils, instead of moving air through ducts. hvac
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I²C (I2C) bus A simple two-wire bus for connecting a processor to many low-speed chips on the same board, such as sensors, small memories and battery gauges. embedded IEC 62133 (portable battery safety) The international safety standard for portable rechargeable cells and batteries; Part 2 covers lithium and is widely required for battery products. certification IEC 62368-1 The international safety standard for audio/video, IT and communication equipment; it replaced IEC 60950-1 and IEC 60065 with a hazard-based approach. certification In-circuit test (ICT) Automated electrical test of an assembled circuit board that checks individual components and connections for shorts, opens and wrong or missing parts. manufacturing Incoterms Standard trade terms published by the International Chamber of Commerce that define who pays for, and bears the risk of, each stage of shipping goods. manufacturing Injection mold tooling (soft vs hard) The molds that make plastic parts; soft tools are cheaper and faster but wear sooner, hardened steel tools cost more and last far longer. mechanical Injection molding Forcing molten plastic into a metal mold to make identical parts in seconds: very low cost per part, but significant upfront tooling cost and lead time. mechanical Integral windup When an actuator hits its limit, a PID's integral term keeps accumulating error, causing large overshoot and slow recovery once the limit is released. controls Intentional vs unintentional radiator FCC categories: intentional radiators deliberately transmit radio signals; unintentional radiators generate RF energy internally but aren't meant to emit it. certification Interrupt A hardware signal that pauses the processor's current work to handle an urgent event right away, such as a button press, timer tick or arriving data. embedded IP rating (ingress protection) A two-digit code defined in IEC 60529 that rates an enclosure's protection against solid objects and dust (first digit) and water (second digit). mechanical ISED certification (Canada) Canada's radio and EMC approval regime, run by Innovation, Science and Economic Development Canada; similar to FCC rules, with its own requirements. certification
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Kalman filter (state estimation) An algorithm that combines a model with noisy measurements to estimate a system's state better than either alone; the basis of most sensor fusion. controls kW vs kWh (power vs energy) Kilowatts measure power, the rate of energy use at a moment; kilowatt-hours measure energy used over time. Commercial electricity bills often charge for both. hvac
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Landed cost The full cost of getting a unit to your warehouse: factory price plus freight, insurance, duties, tariffs, customs fees, brokerage and handling. manufacturing LDO (low-dropout regulator) A simple linear regulator that gives a clean, low-noise output slightly below its input voltage; efficient only when the voltage drop across it is small. power Lead time The time between placing an order and receiving it; for some parts, tooling and production slots it runs to months and dictates the schedule. electrical LFP vs NMC (lithium-ion chemistries) Two common lithium-ion chemistries: NMC packs more energy into less space and weight; LFP offers longer cycle life, lower cost and better thermal stability. power Li-ion cell vs battery pack A cell is one electrochemical unit; a pack combines cells in series and parallel with protection, wiring and housing to reach the voltage and capacity needed. power Local LLM Running a large language model on your own hardware rather than through a cloud API, for privacy, offline operation, cost control or latency. ai LoRa and LoRaWAN Long-range, low-power, low-data-rate wireless in unlicensed sub-GHz bands, suited to sensors that send small messages infrequently over long distances. embedded Low Voltage Directive (LVD) The EU electrical-safety directive (2014/35/EU) for equipment rated 50–1,000 V AC or 75–1,500 V DC; lower voltages fall under other safety rules. certification LTE-M and NB-IoT (cellular IoT) Low-power cellular standards from 3GPP for devices that need wide-area coverage without Wi-Fi, using licensed spectrum on existing mobile networks. embedded
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mAh vs Wh (battery capacity) mAh measures charge at a cell's voltage; Wh measures energy (Wh = V × Ah). Use Wh to compare batteries and to check shipping and airline limits. power Manual J load calculation The ACCA method for calculating a home's heating and cooling loads room by room to size equipment; Manuals S and D cover equipment and ducts. hvac Mass production (MP) The stage after PVT where the factory builds at full rate, with ongoing quality control, change management and cost reduction. manufacturing Matter An open smart-home standard from the Connectivity Standards Alliance that lets certified devices work across major ecosystems over Wi-Fi, Thread or Ethernet. embedded Microcontroller vs microprocessor (MCU vs MPU) An MCU is a self-contained chip with built-in memory running bare-metal or RTOS firmware; an MPU needs external memory and usually runs a full OS such as Linux. embedded Minimum order quantity (MOQ) The smallest quantity a supplier will sell or produce in one order; MOQs on parts, packaging and production runs shape early cash needs and unit cost. manufacturing Modbus A simple, long-established open protocol for reading and writing registers in industrial and energy equipment, over RS-485 serial (RTU) or Ethernet (TCP). embedded Model predictive control (MPC) A control method that repeatedly optimizes actions over a short future horizon using a model, respecting limits while minimizing a cost such as energy or error. controls Model quantization Running an AI model at lower numeric precision, such as 8 or 4 bits instead of 16 or 32, to cut memory and speed up inference at some cost in accuracy. ai Motor driver (H-bridge) The power electronics between a controller and a motor, switching current to set speed, direction and torque while protecting against faults. electrical MQTT A lightweight publish/subscribe messaging protocol widely used to move telemetry and commands between connected devices and the cloud through a broker. embedded MVP vs EVT An MVP tests whether customers want the product; EVT tests whether a production-intent design works. Mixing them up wastes tooling or ships prototypes. business
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NRE (non-recurring engineering) One-time costs to develop a product and prepare it for production, such as design, tooling, fixtures and certification, as distinct from per-unit costs. manufacturing NRTL safety certification (UL, ETL) In the US, independent product-safety certification by an OSHA-recognized Nationally Recognized Testing Laboratory; UL and ETL marks are common examples. certification
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OCPP (Open Charge Point Protocol) An open protocol, maintained by the Open Charge Alliance, for communication between EV chargers and the central systems that manage them. power ODM (original design manufacturer) A manufacturer that designs and builds a product, often from an existing platform, for you to sell under your brand; fast, but you may not own the design. manufacturing Over-the-air (OTA) update Delivering new firmware to devices in the field over their network connection, so bugs and security issues can be fixed without a recall. embedded Overshoot How far a system's output goes past its target after a change, usually stated as a percentage of the size of the step. controls
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PCB layout Placing components and routing copper connections on a printed circuit board, producing the fabrication and assembly files a factory builds from. electrical PCB stack-up The arrangement of copper layers and insulating material in a circuit board, which sets cost, signal integrity, EMC performance and trace impedance. electrical PID control The workhorse feedback algorithm: it combines present error (P), accumulated past error (I) and rate of change (D) to compute the actuator command. controls PLC (programmable logic controller) A rugged industrial controller that runs logic for machines and processes, programmed in standardized languages such as ladder diagram and structured text. software Power budget An accounting of how much power each part of a product draws in each operating mode, used to size batteries and supplies and to predict battery life. power Power over Ethernet (PoE) Delivering DC power and data over one Ethernet cable under IEEE 802.3 standards, so cameras, access points and sensors need no separate supply. power Pre-certified radio module A ready-made radio subassembly already certified with FCC, ISED and others, so a product can reuse its approvals instead of certifying a custom radio. certification Pre-compliance testing Informal, lower-cost testing of prototypes against certification limits before the formal lab test, to find and fix problems while changes are still cheap. certification Predictive maintenance Scheduling maintenance from the measured condition of equipment, such as vibration, temperature or current, instead of fixed intervals or waiting for failure. ai Product requirements document (PRD) The document stating what a product must do, for whom and under what conditions, so engineering, suppliers and certification share one target. business Pulse-width modulation (PWM) Switching a signal fully on and off very fast and varying the on-time (duty cycle) to control average power to motors, LEDs, heaters and converters. embedded PVT (production validation test) A pilot run on the real production line, at production pace, to prove the factory can build the product consistently at target yield and quality. manufacturing
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Radio Equipment Directive (RED) The EU directive (2014/53/EU) for products that transmit or receive radio, covering spectrum use, EMC, safety and, for now, some cybersecurity. certification REACH (SVHC) The EU chemicals regulation; for hardware makers, the main effect is disclosure duties when products contain listed substances of very high concern above 0.1%. certification Real-time operating system (RTOS) A lightweight operating system for microcontrollers that schedules tasks with predictable timing; the alternative is bare-metal code in a single main loop. embedded Refrigerant transition (low-GWP) The shift from high global-warming-potential refrigerants to lower-GWP ones, driven in the US by the AIM Act, changing HVAC design, safety and service. hvac Reliability testing (HALT, burn-in) Stressing products with heat, cold, humidity, vibration and repeated cycling to find weak points and early failures before customers do. manufacturing Retrieval-augmented generation (RAG) Having a language model answer from documents retrieved for each question, such as manuals and specs, rather than from memory, so it can cite sources. ai RoHS EU rules restricting ten hazardous substances, including lead, mercury and cadmium, in electrical and electronic equipment, per homogeneous material. certification RS-485 A differential electrical standard for long, noisy, multi-device serial links; the physical layer under Modbus RTU, BACnet MS/TP and many industrial devices. embedded
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SBOM (software bill of materials) A machine-readable inventory of every software component, library and version in a product, used to track vulnerabilities and licenses. software SCADA Software and networks that supervise and control distributed industrial equipment, collecting data from PLCs and remote units and presenting it to operators. software Schematic The logical diagram of an electronic circuit showing every component and connection; the source of truth that the PCB layout and BOM are built from. electrical Second source A qualified alternative supplier or part for a component, so production can continue if the primary source is unavailable, discontinued or repriced. electrical SEER2 and HSPF2 US seasonal efficiency ratings for air conditioners (SEER2, cooling) and heat pumps (HSPF2, heating), measured under the DOE test procedure in force since 2023. hvac Sensible vs latent load Sensible load changes air temperature; latent load is moisture to remove. Cooling must handle both, and humidity complaints often trace to latent load. hvac Setpoint The target value a control system tries to hold, such as a temperature, speed or pressure; the controller acts on the gap between setpoint and measurement. controls Sheet metal fabrication Making parts by cutting and bending flat metal sheet; cost-effective for enclosures, brackets and chassis from prototype through moderate volumes. mechanical Sleep current The current a battery product draws while idle; in devices that sleep most of the time, it often decides battery life more than active power does. power SMT assembly (PCBA) Building circuit boards by machine-placing surface-mount components and soldering them in a reflow oven; the standard process for modern electronics. manufacturing SPI (Serial Peripheral Interface) A fast, simple board-level bus in which a controller talks to peripherals such as flash memory, displays, radios and high-speed sensors. embedded State-space model A description of a dynamic system by its internal state variables and how they evolve; the basis for multi-input control and state estimation. controls Step response How a system's output behaves after a sudden change in input or setpoint; the standard way to measure a control loop's speed, overshoot and accuracy. controls System identification Building a mathematical model of a real system from measured input and output data, so controllers can be designed and tested before risking hardware. controls
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Telemetry Data that devices send home about their status, usage and environment, used to monitor fleets, debug field problems and improve products. software Test fixture Custom hardware that holds a board or product and connects it to test equipment, so every unit can be tested quickly and repeatably on the production line. manufacturing Thermal management Getting heat out of electronics, motors and batteries so every component stays within its temperature limits over the product's life and environment. mechanical Thermal runaway (lithium-ion) A self-sustaining reaction in which a damaged or abused lithium-ion cell overheats uncontrollably, often venting, catching fire and spreading to other cells. power Thermostat setback Automatically lowering the heating setpoint, or raising the cooling setpoint, when a space is empty or people are asleep, to save energy. hvac Thread A low-power IPv6 mesh networking protocol on IEEE 802.15.4 radios, widely used for smart-home devices and as a transport for Matter. embedded Time-series database A database optimized for timestamped measurements such as sensor readings, storing and querying large volumes of data over time efficiently. software TinyML (on-device machine learning) Running small machine-learning models on microcontrollers and low-power chips for tasks like keyword spotting or anomaly detection, without the cloud. ai Tolerance stack-up Adding up the allowed variation of every part in an assembly to check that things still fit, seal and work when all the tolerances combine. mechanical
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UART (serial port) The simplest asynchronous serial link between two devices, used for debug consoles and GPS or cellular modules, and as the basis for RS-232 and RS-485 links. embedded UKCA marking Great Britain's post-Brexit conformity mark; for most electronics the UK now accepts CE marking indefinitely, so UKCA is generally optional. certification UN 38.3 (lithium battery transport testing) The UN test series that every lithium cell and battery design must pass before it can legally be shipped by air, sea, rail or road. certification Undercut (side actions) Any feature that stops a molded part ejecting straight out of the mold, such as a side hole or snap hook; it needs extra tool mechanisms or a redesign. mechanical Unit economics (hardware) The revenue and costs attributable to selling one unit, showing whether each sale makes or loses money before fixed costs. business USB Power Delivery (USB PD) A USB-C protocol that lets a charger and device negotiate voltage and current, up to 100 W at standard power and up to 240 W with Extended Power Range. power
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Wall thickness, ribs and sink marks Molded parts should keep walls uniform and ribs thinner than the wall they support; thick sections cool slowly and cause sink marks, voids and warping. mechanical Watchdog timer A hardware timer that resets the processor if the firmware stops checking in, so a hung device recovers by itself instead of staying frozen. embedded WEEE The EU directive (2012/19/EU) making producers pay for the collection and recycling of their electrical and electronic products at end of life. certification Wi-Fi Wireless LAN based on IEEE 802.11 that gives devices direct internet access through existing routers, at the cost of higher power use than BLE or Thread. embedded Working capital and inventory cash The cash tied up between paying suppliers and getting paid by customers; in hardware, deposits and inventory can consume cash long before revenue arrives. business Works-like vs looks-like prototype Early prototypes are often split: a works-like build proves function and ignores looks; a looks-like model shows final form without working insides. business