MFD

See Microfarad.

MHD

Medium Hard Drawn copper wire.

MHO

The unit of conductance, equal to the reciprocal of the unit of resistance (ohm).

MHz

See Megahertz.

Mi-II System

Premium line 2.0 mm pitch connector system, originally introduced for the office automation market in multi-branch harnessing. Includes wire-to-board, crimp, and IDT products, single and dual row configuration.

Micro

Prefix meaning one millionth.

Micro Shunt

See Jumper.

Microamp

One millionth of an ampere. Abbreviated: ua.

Microbending

In an optical waveguide, sharp curvatures involving local axial displacements of a few micrometers and spatial wavelengths of a few millimeters. Such bends may result from waveguide coating, cabling, packaging, installation, etc.

Microcircuit

Synonym for integrated circuit.

Microelectronics

Synonym for integrated circuit.

Microfarad

One-millionth of a farad. Abbreviations include: uf, ufd, mr, and mfd.

Microhenry

One millionth of henry. Abbreviated: uh.

Microhm

One millionth of an ohm. Abbreviated: u.

Micromicrofarad

One-millionth of a microfarad. Abbreviated uuf, uufd, mmf, mmfd. Also known as a picofarad Abbreviated pf or pfd.

Micron (µm)  

One millionth of a meter, or 0.000039 inches.

Microphonics

Noise caused by mechanical excitation of a system component. In a single-conductor microphone cable, for example, microphonics can be caused by the shield rubbing against the dielectric, as the cable is flexed.

Microprocessor (MPU)

A large-scale integrated circuit that contains all the elements of a microcomputer, except memory.

Microsecond

One millionth of a second.

Microsectioning

The preparation of a specimen for microscopic examination, usually by cutting out a cross-section, followed by encapsulation, polishing, etching, staining, etc.

Microstrip

A transmission line (popularly used in card/board designs) that consists of two parallel conductive lines/planes separated by a dielectric. The narrow conductive strip(s) is the signal conductor on plane 1; and the wider strip is the signal ground current return path on plane 2 . From a noise immunity/shielding point of view, this "open" transmission line design is not as effective as the stripline design, which sandwiches the signal line with two ground lines/planes.

See also Transmission Line, Stripline.

Migration

The movement of atoms or molecules of a metal from one location to another that changes the properties of the metal. Nickel underplating prevents the migration between tin or gold platings and the base material.

MIL

  1. A unit of length equal to one thousandth of an inch.
  2. Military

MIL SPEC

Specific manufacturing, testing, and packaging requirements set by the U.S. military as indicated on an item by a military identification or MIL SPEC number.

MIL STD

A standard specification set by the US military for manufacturing, testing, and packaging requirements for products intended for military use.

MIL STD 883

US military standard for high reliability semiconductors and integrated circuits. Three classes of quality are "A" for aerospace applications, "B" for avionics, and "C" for ground equipment.

Military Specifications

See MIL SPEC.

Milli

Prefix meaning one thousandth.

Millihenry

One thousandth of a henry. Abbreviated: mh.

Milliohm

One thousandth of an ohm. Abbreviated: m.

Millisecond

One thousandth of a second. Abbr: msec.

Millivolt

One thousandth of a volt. Abbreviated: mv.

Mini-DIP

A plastic surface mount package with ribbon leads on two sides, on 0.070" centers.

Mini-Fit

A Premium line high current, high density power connector family.

Mini-T Terminal

A Premium line input/output contact for use in automotive applications.

Minimum Annular Ring

The minimum width of metal, at the narrowest point, between the edge of the hole and the outer edge of the terminal area.

Minor Defect (Cosmetic)

A defect that is not likely to reduce the usability of a product for its intended purpose. It may be a departure from established standards, but has no significant bearing on the effective use or operation of the unit.

Mirror Image Die

A type of stamping die in which multiple terminals are designed with two identical rows facing or with back-to-back. The raw material width is approximately double the extended width of each terminal.

Misalignment Loss

In fiber optics, a signal loss attributed to the lateral or angular misalignment of the optical junction center line.

Mismatch

In terms of connector impedance, the fact that a terminal or connector has a different impedance from that for which is was designed.

Mixed Signal

The combination of moderate to high current rating and a low contact resistance that allows the customer to run signal and power in the same connector housing simultaneously.

ML

Single-conductor, paper-lead cables twisted together, no overall covering.

MLB

Multilayer Board

See Multilayer PCB.

mm

Millimeter

MM

Mining Machine cable

MMF or MMFD

Abbreviation for micromicrofarad, one millionth of a farad. Also called picofarad. Abbreviated pf or pfd.