Get electricity reviews and study guides here. Learn about electricity or brush up on your skills. Thorough explanations and practice examples will help you review physics.

Study Guides

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  • 1.

    Electromagnetic Fields Help

    Electromagnetic Fields The optical telescope was invented long before scientists knew that visible light represents only a tiny part of a continuum of energy wavelengths. Isaac Newton believed that visible light was composed of tiny particles or ...

  • 2.

    What Does Electricity Do? Help

    Introduction Let's delve into the workings of things that can’t be observed directly. These include particles, and forces among them, that make it possible for you to light your home, communicate instantly with people on the other side ...

  • 3.

    Electrical Diagrams Help

    Electrical Diagrams To understand how electric circuits work, you should be able to read electrical wiring diagrams, called schematic diagrams . These diagrams use schematic symbols . Here are the basic symbols. Think of them ...

  • 4.

    How Resistances Combine Help

    Introduction When electrical components or devices containing dc resistance are connected together, their resistances combine according to specific rules. Sometimes the combined resistance is more than that of any of the components or devices ...

  • 5.

    Kirchhoff’s Laws Help

    Introduction The physicist Gustav Robert Kirchhoff (1824-1887) was a researcher and experimentalist in electricity, back in the time before radio, before electric lighting, and before much was understood about how electric currents ...

  • 6.

    Direct Current Practice Test

    Review the following concepts if needed: What Does Electricity Do? Help

  • 7.

    Alternating Current Help

    Introduction Direct current (dc) can be expressed in terms of two variables: the polarity (or direction) and the amplitude . Alternating current (ac) is more complicated. There are additional variables: the period ...

  • 8.

    Waveforms Help

    Introduction If you graph the instantaneous current or voltage in an ac system as a function of time, you get a waveform. Alternating currents can manifest themselves in an infinite variety of waveforms. Here are some of the simplest ones. ...

  • 9.

    Fractions of a Cycle Help

    Introduction Scientists and engineers break the ac cycle down into small parts for analysis and reference. One complete cycle can be likened to a single revolution around a circle. Sine Waves As Circular ...

  • 10.

    Amplitude Help

    Introduction Amplitude also can be called magnitude, level, strength , or intensity . Depending on the quantity being measured, the amplitude of an ac wave can be specified in amperes (for current), volts (for voltage), or ...

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