Graphic Design & Printing TechnologyUnit - 5
Basic Engineering........................................................................
Introduction
An understanding of simple electric, electronic, mechanical and pneumatic
components provides the background necessary to explore more complex
system of components used in various equipment and machineries used in the
printing industry.
Learning Outcomes
The learner:
- distinguishes between Alternating current and Direct current.
- understands the functions of Motors and Transformers.
- identifies Basic Electronic Circuit components.
- recognises Mechanical components.
- recognises Hydraulics and Pneumatics.
- recognises Mechanical, Electrical, Electronic and Pneumatic parts of a
printing machine.
Alternating current and Direct current
Alternating current and Direct current: Alternating current (AC) is an electric
current in which the flow of electric charge periodically reverses direction,
whereas in direct current (DC) the flow of electric charge is only in one direction.
AC is the form in which electric power is delivered to businesses and residences.
The usual wave form of AC in most electric power circuit is a sine wave. In
certain applications, different wave forms are used, such as triangular or square
waves. The rate at which the electric current changes its direction per second
is called frequency and it is denoted in Hertz. The electric supply that we get
at our home is usually 230 volts and its frequency is 50 Hz.
Direct current (DC) is the unidirectional flow of electric charge. DC is produced
by sources such as batteries, power supplies, thermocouples, solar cells, or
dynamos. DC may flow in a
conductor such as a wire, but can
also flow through semi
conductors, insulators, or even
through a vacuum as in electron
or ion beams. The electric
current flows in a constant
direction, distinguishing it from
AC.