This book provides a comprehensive and timely basic overview of required knowledge for the use of Programmable Logic Controller(PLC), Microprocessor(8085) & Micro controller. The handbook covers the scientific principles and technologies that are necessary to implement. A comprehensive and definitive coverage of this emerging field is provided for both academic and practicing technicians of industry. This ―Study Guide is designed to provide the programming methodology used in industry with a review of and an introduction of basic programs of PLC, Microprocessor & Microcontroller. After successful completion, the troubleshooter can improve their understanding of PLC, Microprocessor & Micro Controller and related technology.