H

  1. Symbol designation for Magnetic intensity and henry.
  2. Shielded power cable.

Hall Effect Switch

A switch in which the close proximity of a magnetic field to a current carrying metallic strip develops a voltage across the edges of the strip for use as a switching signal.

Halon

Du Pont registered trademark for an inert fire-extinguishing gas used in protecting computer rooms from fire.

Hard Mark Strip

A noncontinuous helical stripe applied to a conductor for identification.

Hard Soldering

Process of joining two metals by utilizing an alloy with a melting temperature higher than 800° F (427° C).

See also Soft Soldering.

Hardener

A chemical added to "cure" a thermosetting resin., i.e., it reacts with specific functional groups in the resin to chemically create cross-links which results in a 3-dimensional polymer network. Since a phase change usually occurs, a liquid pre-preg or stage B resin is said to be "hardened" by use of the hardener. In this process it changes to a stage C resin.

Hardness

Resistance of material to plastic deformation, usually by indentation.

Hardware

Components such as shells, guide pins, polarizing pins, strain relief clamps, mounting screws, etc. that are used with connectors.

Harness

A group of wires and cables, usually made with breakouts, which are tied together or pulled into a rubber or plastic sheath. A harness provides interconnection of an electric circuit.

Hash

A type of electrical interference produced by man-made devices, particularly those which experience arcing as contacts open and close. Automotive voltage regulators and power-supply vibrators are two common examples.

HD

High Density. Refers to the high density packaging technology.

See also Density.

HDD

Hard Disk Drive

HDTV

High Definition Television. Digital TV with high resolution due to a high number of pixels that create the picture.

Head Stack

The process of using a dual-sided, nailed header for stacking connectors (on wire or to PCB) on each side of the header.

Headend

The central facility where signals are combined and distributed in a cable television system.

Header

The male connector assembly, also called a post, of a two-piece post-and-box connector attached to a PCB. Headers are available in two styles: shrouded and unshrouded. On shrouded headers, the pins are surrounded by a housing-like casing on at least three sides. Some unshrouded headers have a friction locking device.

Header Duct

The main duct used to bring cable from a wiring closet to distribution ducts in a cellular or underfloor duct system. Also called a feeder duct.

Heat and Pull

Desoldering method that uses a soldering iron with a shaped heater block attached, a molten solder pot or solder fountain, or a device that grasps, heats, and pulls the leads of the component to be removed.

Heat Distortion

The deformation of a material due to the application of heat, as specified by the ASTM standard. 

Heat Endurance

The amount of heat-aging time a material can withstand before failing a specific physical test. Heat endurance is an important consideration during oven soldering of terminations.

Heat Resistant Terminal

A copper or brass terminal that is nickel plated to withstand 650° Fahrenheit.

Heat Sink

A device that radiates or draws heat away from a source, such as a transistors or power diode. Heat sinks are used to increase effective surface area, which increases heat radiating capability, of components. Heat sinks are made of high-thermal-conductivity metals, usually aluminum.

Heat Soak

Heating a circuit to a specific temperature and then over a period of time to allowing all parts of the package and circuit to stabilize at that same temperature.

Heat Staking

The process of melting and deforming the plastic pegs on a connector to secure and lock it onto a PCB in preparation for soldering.

Helical Stripe

A continuous, colored, spiral stripe applied to a conductor for circuit identification.

Henry (H)

A practical unit of inductance that will produce a voltage drop of one volt when the current changes at the rate of one ampere per second.

Hermaphroditic

A connector or contact in which both mating parts are identical at their mating surfaces. Also called sexless connector or unisex connector.

Hermetic

Air tight. Since all materials are permeable, specifications define acceptable levels of hermeticity.

Hermetic Seal

Hermetically sealed connectors are usually multiple contact connectors where the contacts are bonded to the connector by glass or other materials, making them air tight.

Hermetically Sealed Switch

A switch completely sealed to provide constant operating characteristics.

Hertz

The basic unit of frequency measurement used in communications transmission. One hertz is a frequency of one cycle per second. One kilohertz equals 1,000 hertz. One megahertz equals 1,000,000 hertz. One gigahertz equals 1,000,000,000 hertz.

See also BPS.

HET

High End Telecommunications

Heterogeneous Insulation

A cable insulating system composed of two or more layers of different materials.

See also Homogeneous Insulation.

HF or hf

  1. High Frequency. The range between 3 and 30 million hertz (3-30 MHz).
  2. Polyethylene insulated radio hookup wire.

Hi Pot

A dielectric strength test that tests the insulation between two circuits.

Hi Rel

Abbreviation for high reliability. Characterized by extremely tight tolerances and long service life.

Hi Temp

A terminal, usually made of nickel or nickel alloys, designed to tolerate extremely high temperatures.

High Energy Surface

A solid with high surface free energy, usually hard and with a high melting point, which means a surface of a substrate with a high degree of wettability important for the adherence and working of an adhesive. Including metals, metal oxides, nitrides, and glasses that are arbitrarily defined as having surface-free energies in the range 5000-500 ergs/cm2.

High Frequency

The band from 3 to 30 MHz in the radio spectrum, as designated by the Federal Communications Commission.

High-Current Terminal Block

A terminal block designed especially for high voltage applications. Designed with clamp or lug connections.

See Low Energy Surface.

Histogram

A bar chart that reflects the location and shape of a frequency discontinuous distribution.

Hold Current

The minimum current that will keep relay contact springs energized. Also called electrical hold value.

Holding Strength

Ability of a connector to remain assembled to a cable when under tension.

Hole

  1. A positive charge carrier in a P-type semiconductor material.
  2. The space in an atom left vacant by a departed electron.

Hole Size "D"

The dimension labeled "D" on the Mechanical Dimensions drawing.

Homogeneous Insulation

A completely integrated cable insulation whose components cannot be identified as layers of different materials

See Heterogeneous Insulation.

Homologation

Bringing the structured, but different, requirements (including manufacturing methods) of both partners together to produce an identical product.

Hood

An enclosure attached to the back of a connector to contain and protect wires and cable attached to the terminals of the connector. A cable clamp is usually an integral part of a hood.

Hook Terminal

Terminal with a hook-shaped tongue.

Hook Tongue

Type of terminal with a tongue that opens from the side rather than from the end.

Hostile Environment Connectors

Connectors designed and engineered for operation in hostile environmental conditions, such as extreme low temperatures of absolute zero and severe water tight conditions and/or a corrosive environment.

Hot Bar Soldering

Technique by which a conductive heating process uses a hot bar to solder all flat cable conductors simultaneously to terminals of a flat connector.

Hot Line Clamp

A connector that may be installed or removed by means of an insulated stick while the conductor is energized. Also called live-line connector.

Hot Plugging

Adding electronic components to a system (plugging) or removing electronic components from a system (unplugging) while the system is powered up (hot). Hot plugging enables devices to be swapped without electrical damage to the devices or the main system and without a significant interruption of system operation. Outside the US, hot plugging is known as live insertion or live mating. Also known as live-line connection.

Housing

A device, usually plastic, used to contain and insulate electrical contacts. Also used for mating or locking with a specified mating connector. Housings are also called shells.

HPD

Rubber and asbestos-insulated heater cord. 12-18 AWG, 2, 3 or 4 conductors, 90° C rating, 300 in. May also be produced in no-asbestos version.

HPN

Two or three conductor, neoprene insulated parallel heater cord. 300 in, 90° C, 12-18 AWG.

HS

Rubber insulated heater cord. 300 in, 90° C singles, 60 or 75° C jacket, 12-14 AWG, 2, 3 or 4 conductors.

HSJ

Rubber insulated heater cord. 300 in, 90° C singles, 60 or 75° C jacket, 16-18 AWG, 2, 3 or 4 conductors.

HSJO

Rubber insulated heater cord, neoprene jacket. Otherwise same as HSJ.

HSO

Neoprene jacketed heater cord. Otherwise same as HS.

HSSI

High Speed Serial Interface. A standards reference for WAN or ATM communication protocol. Uses a SCSI-2 style connector as a standards interface.

HT

High frequency.

Hubbing Device

Any device that creates a star network. Also called a hub, multi-station access unit (MAU), multi-port repeater, concentrator, or intelligent hub.

Hum

A term used to describe the 60- or 120-cps sound present in the sound of some communications equipment. Usually hum is the result of undesired coupling to a 60-cps source or to the defective filtering of l20-cps ripple output of a rectifier.

Humidity Resistance

The maximum percent of relative humidity, at a specified temperature and time duration, that a switch will withstand without failing electrically or mechanically.

HW

Radio hookup wire with polyvinyl insulation. 2500V.

Hybrid

A method of interconnecting, assembling, and manufacturing electronic circuits in one package by using more than one discrete chip in combination with thick or thin film components formed on the substrate.

Hybrid Assembly

An assembly that consists of a membrane switch plus passive electronic components, such as LEDs and resistors, mounted to a PCB substrate.

Hybrid Cable

Multi-conductor cable that contains two or more types of components.

Hybrid LAN

A LAN with a mixture of topologies or access techniques.

Hygroscopic

Capable of absorbing moisture from the air.

Hysteresis

A process consisting of a closed cycle of states (mechanical, electrical, magnetic, etc.) that shows a cyclic irreversible dissipative energy loss when compared with process total input minus output energy.

Hz or Hz.

See Hertz.