Isolation

The clearance around a pad, track, zone or via that defines the nearest approach allowed by conductors of another signal set.

IPC

The Institute for Interconnecting and Packaging Electronic Circuits, an American organization.

Interstitial Via Hole

A plated through-hole connecting two or more conductor layers of a multilayer printed board but not extending fully through all the layers of base material comprising the board.

Internal Layer

A conductive pattern which is contained entirely within a multi-layer printed board.

Inter-layer Connection

An electrical connection between conductive patterns in different layers of a multi-layer printed board. (See also Through Connection.)

Inter-facial Connection

See Through Connection.

Insulation Resistance

The electrical resistance of the insulating material (determined under specified conditions) between any pair of contacts, conductors, or grounding device in various combinations.

The electrical resistance of the insulating material (determined under specified conditions) as measured between any pair of contacts or conductors.

Inspection Overlay

A positive or negative transparency made from the production master and used as an inspection aid.

Inspection Lot

A collection of units of products bearing identification and treated as a unique entity from,which a sample is to be drawn and inspected to determine conformance with the acceptability criteria.

Assemblies of a specific production run selected for inspection or test as a sample of the entire run.

Initiating

see "activating".

INDEX EDGE

INDEX EDGE MARKER, INDEXING HOLE, INDEXING NOTCH, INDEXING SLOT: See Locating Edge, Location Edge Marker,etc.

Inclusion

A foreign particle in the conductive layer, plating, or base material.

In-circuit Test

A check of specific components(s) or cuicuits(s) within an assembly without their de-coupling from the primary circuit.

Impedance, Characteristic

The resistance of a parallel conductor structure to the flow of alternating current (ac), usually applied to high-speed circuits and normally consisting of a constant value over a wide range of frequencies.

Immersion Plating

The chemical deposition of a thin metallic coating over certain basis metals that is achieved by a partial displacement of the basis metal.     

Indentation

See “Pit”

IC

Integrated Circuit.