A vacuum tube that contains two elements is called a diode and contains a cathode and plate. A vacuum tube that contains three elements is called a triode and contains a cathode, grid, and plate. A vacuum tube that contains four elements is called a tetrode and contains a cathode, control grid, screen grid, and plate.
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The atom is the smallest individual structure that makes up any chemical element while retaining properties of the element. The atom has a nucleus that contains protons and neutrons. Electrons orbit the nucleus at various distances and with varying amounts of energy.
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Despite awareness campaigns, industry statistics and loss summaries, annual safety conferences and numerous industry associations driving the safety message, we still more often than not take a reactive rather than proactive approach to electrical safety. I am not pointing fingers or sermonizing because I was reactive, and I did not take electrical safety as seriously [...]
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In part nine of this series, I discussed the development of the phasor diagram, a graphical representation of voltage or current magnitude in ac circuits at any instant in time. To better understand the uses of a phasor diagram, let’s take a look at the phasor diagrams of typical utility supply voltages. Before doing so, [...]
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Phasors It is time to bite the bullet. Before we can continue into three-phase electrical circuits and calculations, we have to have a solid understanding of voltage and current phase angles. To do this we turn to phasors. I’m not talking about Captain Kirk’s weapon of choice. I’m talking about a graphical representation of the [...]
(No Ratings Yet)Inductive reactance Electrical resistance is not the only property of materials that resists the flow of current. Let us consider an experiment. Let’s purchase a 12,000-foot spool of insulated 20 AWG copper wire commonly used as communications wire and pull the wire off the spool and lay it out on the ground. If we take [...]
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Energy In Part 2, I discussed power. A light bulb rated at 100 watts and 120 volts will use 100 watts of power when operating at 120 volts. If I wanted to operate ten 100-watt light bulbs on a gasoline powered generator, the rated power output of the generator would have to be at least [...]
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Most of my training in college was in electronics. When I graduated in 1971, most of the electronics companies were not hiring so I took a job with the local electric utility until I could find a job in electronics. Thirty-three years later, I’m still with the utility. Over the years working for an electric [...]
(1 votes, average: 5.00 out of 5)
Up until now, I have been talking about dc, direct current, in which the current in the circuit travels in one direction. Batteries and other sources of dc are marked with what we call polarity marks, + and –. When a battery is connected in a circuit, the current comes out of the positive (+) [...]
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In Part 2 of this series in the September/October issue, I worked through two simple example voltage-drop calculations. In both examples, I calculated what voltage I would have to have at the house to insure the voltage of 120 V at the chicken coop. Let’s call this calculation method A. The reason I used method [...]
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IAEI, as the keystone of the electrical industry, is a membership driven, non-profit association promoting electrical safety throughout the industry by providing premier education, certification of inspectors, advocacy, partnerships and expert leadership in Electrical Codes and Standards development.
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