-E-

Electroless Nickel Immersion Gold ~ A coating applied during printed circuit board manufacture to protect copper features from oxidation and provide a very flat surface for soldering components.

Electro-Magnetic Field  (EMF) ~ The magnetic fields  created by  power lines, transformers, appliances, etc... All electrically charged particles are surrounded by electric fields.  Charged particles in motion produce magnetic fields.

Electro-Magnetic Interference  (EMI) ~ Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics/electrical equipment.

Electro-Static Discharge (ESD) ~ A low-current high-voltage discharge of electricity from an object or person.  ESD can measure up to 20,000 Volts and can damage electronic components, specially CMOS.

Electrolytic Capacitor ~ A capacitor having an electrolyte between the two plates. Thin layer of oxide is deposited on only the positive plate. The oxide acts as the dielectric for the capacitor.  Electrolytic capacitors are polarized.

Electron ~ The smallest sub atomic particle of negative charge that orbits the nucleus of an atom.  Electrons travel at a fairly constant speed, about 20 centimeters or 8 inches per nanosecond, not the speed of light.

Embedded System ~ A specialized computer system that is part of a larger system or machine. Typically, an embedded system is an application specific single-board computer containing the microprocessor, memory, and all interface circuitry with the programs stored on-board as well.  The embedded system can also be a single integrated circuit, called an SOC or System on chip.

Emitter ~ One of the pins on a transistor, along with collector and base. The emitter is the point the transistor connects to the main circuit to return amplified signal voltage. It is the exit point from the transistor.

Energy ~ The capacity to do work.

Eutectic ~ The minimum melting point of a combination of two or more metals.

-F-

Fall-time ~ Time it takes the falling edge of a pulse to go from 90% of peak voltage to 10% of peak voltage.

Farad (F) ~ Unit used to measure capacity or capacitance.

Ferrite Bead ~ Ferrite composition in the form of a bead.  Running a wire through the bead increases the overall inductance.

Fiducial ~ Printed circuit board marking used for component alignment with component pick and place machinery, typically they are .040" Round Pad with .080" Soldermask Relief).  Fiducial types are global, local, and stencil.

Field Effect Transistor (FET) ~ A bipolar transistor used as a current amplifying device.

Fibre Channel (FC) ~ A high-speed data transfer interface that can be used to connect together workstations, mainframes, supercomputers, storage devices and displays. The communications standard operates between 133 Megabits/sec to 1062 Megabits/sec. Transfer distances up to 10 km are possible.

Field Programmable Gate Array (FPGA) ~ A programmable integrated circuit consisting of an array of logic cells which can be connected together with a programmable interface.

Filter ~ An electronic circuit used to block certain undesirable signal frequencies.

Flip Chip (FC) ~ Microchip design developed by Intel for its faster microprocessors in which the hottest part of the chip is located on the side that is away from the motherboard.

Flip Flop (FF) ~ A bi-stable multi-vibrator.  A circuit which has two output states and is switched from one to the other by means of an external signal (trigger).

Footprint ~ The mechanical outline physically representing an electronic component on a printed circuit board.  It contains all mounting pads, drill holes, silkscreen, courtyards, and reference designator.

Foundry ~ The manufacturer of Integrated Circuits or Computer Chips.

Frequency ~ The number of complete cycles per second in alternating current (AC) direction. The standard unit of frequency is the hertz (Hz).

FR4 ~ Literally, Flame Resistant Composition 4, an epoxy resin used to make printed circuit boards.

Fundamental Frequency ~ The lowest frequency in a complex waveform.

-G-

Gain ~ Increase in voltage, current and/or power. Gain is expressed as a ratio of amplifier output value to the corresponding amplifier input value.

Gigabyte (GB) ~ 1 billion bytes (109).

Grid ~ An orthogonal network of two sets of parallel lines for positioning features on a printed board.  Some types are Drafting Grid, Placement Grid, Routing Grid.

Ground ~ An intentional or accidental conducting path between an electrical system or circuit and the earth or some conducting body acting in place of the earth. A ground is often used as the common wiring point or reference in a circuit.

-H-

Harmonic ~ Sine-wave component of a signal that is smaller in amplitude and is a multiple of the fundamental frequency of the signal.

Henry ~ Unit of measure for inductance.

Hermetic ~ Sealed so an object is gas tight to a specific rate.

Hertz (Hz) ~ Unit of measure for frequency.  One hertz is equal to one cycle per second.

High Pass Filter (HPF) ~ A tuned circuit designed to pass all frequencies above a designated cut-off frequency.  Frequencies below the cut-off frequency are rejected or attenuated.

Hot Air Solder Level (HASL) ~ Process of flattening or evening out the solder coating on printed circuit board lands/pads by blowing hot air across the board.

Hysteresis ~ Amount that the magnetization of a material lags the magnetizing force due to molecular friction.  In a Schmitt Trigger circuit, it is the difference between the upper and lower trigger points.

 

These definitions were compiled from the internet and CADKraft Engineering assumes no liability in their accuracy nor their completeness.