Sometimes, things that ought to get stuck in your memory just need to get written down (again)… For instance, about a decade ago I learned about the basic physics of electricity - and even applied them to several jobs (mostly in the form of electricity-to-sound for home theater systems). Well, turns out some of that information has gone by the wayside, so here’s a quick refresher.
Fundamentally electricity is all about moving around electrons. Conductive material allows electrons to flow, non-conductive material halts that progression.
The key measures of power in a system are voltage, wattage, resistance, and amperage. Voltage is the measure of potential energy. Wattage is the power of the system. Amperage is the measure of electric charge per second. Each of these elements works in unison with the others to form the equation: P = V x I, where P is wattage, V is voltage, and I is amperage. This means that in a 12V system (V is voltage) at an intensity of 4A (amps) yields 48Watts. The equation can also be used in various other ways so that if you have any 2 out of the 3 functions, you can derive an answer. P / I = V is another example, a 40Watt bulb drawing 4A = 10Volts.
The other important part of electrical systems is resistance, measured in ohms (named after it’s discoverer George Ohm). Resistance is demonstrated by the symbol Ω. Resistance is measured by the difference between points in a system generating 1 volt with 1 amp of power.
Also important to understanding the functional usefulness of electricity in energy systems is the difference between direct current (DC) and alternating current (AC). Solar cells, for instance, produce direct current. DC is the one-directional flow of electrons through a system. Alternatively, alternating current is a varying method of electrical transfer, which can be best represented in a waveform. AC is what goes in to most people’s homes and businesses. So, obviously, between a solar panel or other DC power generation source there must be a transformer that converts the direct current in to alternating current for consumption. Cars, incidentally, operate using direct current - and car batteries are DC batteries (12V, typically).
So, that’s a super quick refresher on electricity. More science lessons to come as I learn them and refresh myself on these topics!
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