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Engineering LibreTexts

1.8: Summary

  • Page ID
    31637
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    An electrical system is one that refers to the direct use of electrical energy in terms of power generation, transmission or application. In contrast, an electronic system is one that tends to use electrical signals as a means to represent, store and manipulate information.

    When measuring physical quantities and in computations, care must be taken to maintain accuracy. Of particular importance are the concepts of resolution and significant digits. Resolution refers to the finest digit place that may be discerned (e.g., tenths or hundredths place). Generally, accuracy increases with the number of significant digits used to represent a value. Leading and trailing zeroes are not considered significant, the exception being trailing zeroes as reported by a measurement device such as a digital multimeter. In computations, results can be no more accurate or have greater resolution than the original values being manipulated. Thus, if the division of two values, each with three significant digits, yields a calculated result with much more than three significant digits, those extra digits only lead to a false sense of accuracy and resolution. As a general rule, the results of multiplication and division will have as many usable significant digits as the least precise of the original values. For addition and subtraction, the resolution of the result can be no greater than that of the original value with the least resolution.

    Scientific and engineering notations are ways of representing values in a compact and less error prone form. They consist of two parts: a mantissa consisting of the significant digits and an exponent, or power of ten, for scaling. Engineering notation further stipulates that the exponent must be a multiple of three, and these multiples use prefix names such as kilo and milli for further simplification. When multiplying or dividing values, the mantissas are multiplied (or divided) while the exponents are added (or subtracted). For addition and subtraction the values are adjusted so that they have the same exponent and the mantissas are then added or subtracted as needed.

    The metric system (or SI) is a measurement system based on powers of ten. Conversions between units of the same type are no longer necessary which simplifies computations. It is a global standard that is ubiquitous in the field of science, engineering and technology.

    The scientific method is a technique used to uncover the reality behind the physical world. It begins with observations of phenomena which then lead to a tentative hypothesis. The hypothesis is tested experimentally with the results either confirming or denying the hypothesis. The process is repeated creating a feedback loop. If the hypothesis is repeatedly verified and not rejected, it may be elevated to a scientific theory. It is important during this process to be aware of logical fallacies and cognitive biases that can lead to false interpretations of the experimental results.

    Finally, RoHS, or the Restriction of Hazardous Substances, is a European Union directive aimed at reducing environmental contamination by restricting the use of certain substances such as lead and mercury. RoHS has a direct impact on the construction and disposal of electrical and electronic products. Other countries and states have similar directives and restrictions in place to help protect the environment.

    Review Questions

    1. Describe the differences between scientific notation and engineering notation.

    2. List the terms and abbreviations (i.e, words and symbols) for engineering notation from 10\(^{−12}\) through 10\(^{12}\).

    3. Give at least one advantage of the metric system over the customary/Imperial system of measurement.

    4. Outline the process of the scientific method.

    5. Explain the differences between a scientific theory, a hypothesis and a fact.

    6. Describe at least three examples of cognitive biases and logical fallacies.

    7. What is RoHS?


    This page titled 1.8: Summary is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by James M. Fiore via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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