- Before a builder can start construction on a house, a structural engineer must design and layout a plan on paper. This "blueprint" diagram tells the builder what type of materials to use, the length and angle of cuts to those materials and pictorial views of wiring routes for electricity and pipes for plumbing. The engineer knows what materials are needed and how they are to be used to give proper structural support to the building. Similarly, electronic engineers use schematic diagrams, which are drawings that show various electronic components and how they are connected together.
- Electronics is a branch of physics that deals with the behavior of electrons and various electronic components. There is no difference between electrons and electricity. The flow of electricity through wires can be thought of as being analogous to the flow of water through pipes. Design engineers map out the various components and how they are connected together in schematic drawings. Technicians build prototypes of the particular device or appliance as designed by the engineer, and any bugs are worked out, which may require some design changes. Once tests are complete, the unit can go into production. The final schematic will then be made available to service technicians in the field who will later use these road maps to troubleshoot problems. For example, a TV repairman may require a schematic diagram when trying to locate a problem with a TV set. The schematic will show him how all of the components are connected. It may also indicate voltage readings and graphic displays of waveforms that should be read by a voltmeter or seen on an oscilloscope at certain various key points. All of these schematic notations can be most helpful to the service technician.
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Schematic symbolsStandard symbols are used in schematic drawings representing many different components. For example, basic components include switches, diodes, batteries, transformers, transistors, resistors and capacitors. Ground connections, antennas, audio jacks and a host of other elements that are found in electronic appliances and devices also have standardized representative diagrams. Schematic symbols are very simple, and often make sense intuitively, as their appearance is reflective of their function. For example, an on/off switch, such as a light switch or a power switch on an appliance, is represented by a single line that is broken with a line drawn upward at a slight angle. In the accompanying drawing, four component symbols are shown. From left to right, top to bottom is a transformer, a transistor, a switch and a diode. Schematic diagrams are key to the design engineer's work, and a very necessary tool in the serviceman's repair shop.
