What year did DC appear?

Function to reverse the binary short integer? What is the difference between a database and word processing? How do you use independent invention in a sentence? Where does the input power go when the mechanical output power is zero? Who are the ancestors of C programming language? What is Class in HTML? What is the water pressure in residential water lines in Calgary AB Canada? Can you install toilet and sink downstairs? What does the word vent mean? Should the trap be before or after vent? What is the difference between butt weld and socket weld? What is the purpose of fiber reinforced plasitc? Is it true that the only way to transfer control from one place in the program to another in OOP is by using goto statement? How much thickness of plates weld by using gas metal arc welding? Define the term regulation as applied to dc power supply? What is the need for optimization? Can the Yield strength of steel ever be greater than the Ultimate tensile strength? What are disadvantage of secure digital? What would happen if the direction of the current through a hall probe is reversed? How you define SCADA?