A hard, natural resin (nowadays also synthetic),consisting of abietic and primaric acids and their isomers, some fatty acids and terpene hydrocarbons, that is extracted from pine trees and subsequently refined.
Rosin_FluxThe mildest of solder fluxes and generally requiring added organic activating agents.
RoadmapA printed pattern of non-conductive material by which the circuitry and components are delineated on a board to aid in service and repair of the board.
Right_angle_Edge_connectorA connector which terminates conductors at the edge of a printed board, which bringing the terminations our at right angles to the plane of the board conductors.
Ribbon_CableA flat cable with round conductors.
RheologyScience of flow ,is the study of the flow and deformation of matter and is particularly important with regard to colloidal systems.
Re_workingThe act of repeating one or more manufacturing operations for the purpose of improving the yield of acceptable part.
Re_workA manufacturing step or process that is repeated to bring a non-performing or non-conforming component or circuit to a functional condition.
Reverse_ImageThe film pattern on a printed circuit board enabling the exposure of conductive areas for subsequent plating.
ResistCoating material used to mask or to protect selected areas of a pattern from the action of an etchant, solder, or plating. Also see Dry Film, Resists, Plating Resists and Solder Resists.
ResinA high-molecular-weight organic material with no specific melting point. A polymer.
Resin_SmearResin transferred from the base material onto the surface or edge of conductive pattern normally caused by drilling. Sometimes called epoxy smear.
ResidueAny visual or measurable form of process-related contamination.
RepeatabilityThe ability of a system to return to a specific parameter, said of equipment when evaluating its consistency of processing.
RepairThe process of restoring the functional capability of a defective component or circuit.
ReliabilityThe probability that a component, device or assembly will function properly for a defined period of time under the influence of specific environment and operational conditions.
Relative_HumidityThe radio of the quantity of water vapour present in the air to the quantity which would saturate the air at the given temperature.
RegistrationThe alignment of a pad on one side of the printed circuit board or layers of a multi-layer board to its mating pad on the opposite side.
Register_MarkA symbol used as a reference point to maintain registration.
Re_flowingThe melting of an electro-deposit followed by solidification.
Re_flow_SpikeThe portion of the re-flow soldering process during which the temperature of the solder is raised to a value that is sufficient to cause the solder to melt.
Re_flow_SolderingJoining components to substrates by placing the parts into solder paste and then melting the paste to achieve re-flow and the interconnection.
Reference_EdgeThe edge of cable or conductor from which measurements are made.
Radial_LeadA lead extending out of the side of a component, rather than from the end.