PCB Design Glossary

Browse the glossary using this index

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Short for Reference Designator.  Every component in every schematic and board file needs a unique identifier.  These can be any alphanumeric character string, but the convention and best practice is to use a letter to indicate the component type and a number that is incremented with each successive component type. 

For example, three resistors on a board would be labeled R1, R2, and R3, even if they had identical values.

Common Reference Designators
Prefix Component
A Assembly
B Battery
C Capacitor
 D Diode
DS  Display
 F  Fuse
FB   Ferrite Bead
J  Jack
 L  Inductor
 MK  Microphone
 TP  Test Point
 U  Integrated Circuit
VR   Voltage Regulator
XTAL   Crystal
 Y  Oscillator


These components restrict current flow between two nets in an electrical circuit.  The amount of current is proportional to the potential difference between the two nets.  Resistors are passive components.

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