SECOND GENERATION COMPUTERS :
These computers used transistors, IC Chips or Integrated circuit chips and Large Scale Integration (LSI).
THIRD GENERATION COMPUTERS:
This generation of computers used Very Large Scale Integration (VLSI) and Super Large Scale Integration (SLSI) technology.
FOURTH GENERATION COMPUTERS:
These computers used microprocessor instead of Printed Circuit Board (PCB). The microprocessor revolution began in 1970 with the introduction of 4004 microprocessor by Intel.