The differrence between PCB and PCBA
PCB is the short name by Printed Circuit Board. PCB mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate.(From Wikipedia) There are several types of PCBs such as single sided, double sided or multilayer PCB.
PCBA is the short name by Printed Circuit Board Assembly.PCBA is a finished product after all solder paste on the bare PCB and with components like resistors, ICs (Integrated Circuits), capacitors,inducer,diode,transformers and any other components,the components using is depending on the application and desired characteristics of the board.
In brief,PCB is a bare board, a semi-finished product;PCBA is a PCB with components,it’s a finished product(such as graphics card,memory bank).