So what is Voltage anyway?
In the last Chapter we learned about the atomic structure of atoms and
bonding and releasing. The reason we care about this atomic bonding and
releasing process is because this process is what makes the electrons move
from one atom to another.
Voltage is a measurement of Electromotive Force (EMF, E, V for volts). More practically you can think about voltage as being the force, the pressure or the amount of push available to move electrons. The terms voltage and volts are much more commonly used today then the term Electromotive Force, however all of these terms are used in technical and scientific publications. A meter called a "volt meter" can be used to measure voltage.
Now, if voltage is this energy providing the potential or pressure, one might ask: 1) where does it come from, and 2) what does this pushy voltage push around?
When we have a situation in which we can generate a large number of electrons with their negative charges, these electrons will have a natural tendency to be attracted toward a place where they can discharge this energy, and return to a state of equilibrium. An equilibrium state is where no uneven charges exist.
When we consider a flashlight battery, there is this unbalanced situation where electrons are available at one terminal (or location) of the battery and the other terminal is available to receive these electrons. This difference between the two terminals is called a potential energy (voltage) and it is measured in volts (V). The battery is a chemical storage device that is holding this potential energy. Within the flashlight there are also some metal strips called conductors, a bulb and a switch. When we press the switch, we connect the battery energy to the bulb. The bulb lights. The bulb will stay lit until the switch is either shut off or until the potential at the battery terminals becomes equalized. As the battery runs down, its ability to push electrons steadily diminishes until the light goes completely out.
So what have we learned about voltage? Voltage pushes electrons. When electrons are available (potential), upon being released, will want to flow along a conductor to a place where they want to be received. In a flashlight, a good battery has potential and when the switch is closed these electrons flow from the battery along the conductors through the switch and the bulb and back to the other terminal of the battery.
What is Current?
Within a wire or a circuit, the amount of electrons that are flowing at any given
time is called the Current. Also within a battery, the Current is the number of
Ions moving through the electrolyte solution, but more about the battery shortly.
Considering our flashlight example, VOLTAGE pushes CURRENT through the conductive
path, the switch and the bulb.
The unit of measure for Current is the Ampere, commonly shortened to Amp and is measured using an Ammeter. The common symbols are A and I. Electrons are very small so to get one Amp of current to flow for one second on time, it takes one Coulomb of electrons per second. In numbers that is 6,250,000,000,000,000,000 electrons.
Consider a storm
The sight and sounds of storms are all about electrons move from a
higher state of charged to a lesser charged state. You may have experienced this
event by seeing the flash of light during a lightning strike, or hearing or feeling
the thunder during a storm. The air around the clouds acts as an insulator thus not
allowing the clouds to discharge their buildup of electrons. The level of
charge(energy) builds higher and higher, becoming so great that it breaks down the
air (and moisture). Along with the flash of light(photon energy) and the sound of
thunder (sound wave energy), there is a great electromagnetic energy burst. If you
were listening to an AM radio during the storm, you would hear the effects of that
electromagnetic energy on you radio's reception.
Electron Flow Vs Conventional Flow
This is a good time to take a moment and clarify the current flow rule used in this
book. The book will be using electron current flow and will not be using conventional
current flow. Thanks to some well documented basic principals laid down by Benjamin
Franklin, we find ourselves at one of these interesting crossroads in science. When
the term CURRENT FLOW is used, we will be talking about current moving through a
conductor, based on the theory of electrons flowing.
So what is the big deal, you might ask?
Franklin wrote about electricity flowing from positive to negative. Even today, when we think about the electrical systems of our automobiles, we think of the negative battery terminal as ground and the positive terminal as HOT. Consider, that in most cars the negative battery terminal is connected to the chassis of the car. This is conventional current flow.
Well, as it turns out, 100 or so years after Ben Franklin the electron current flow was discovered, and those pesky little electrons tend to move from negative to positive. In this day of electronics, many people look at the movement of the electrons. Simply put, the negative terminal is the source of the electrons. Scientific literature speaks about the electron-hole pair so below is an analogy to help you understand the thinking.
OBSCURE THINKING - The Theory of Holes
In real life the Theory of Holes is how to plan a vacation. When my wife and I go on vacation we find a room vacancy, a hole, and fill it. If we want to move around a bit, we need to find another hole (vacant room) and another, until we arrive back at home. Hopefully no one moved in to our home while we were gone. Even though it is the hole or vacancy that is the determining factor in where we stay, we will focus our conversation on the travels, and not on the movement of the hole enabling us to make the moves.
Many games are based on this Theory of Holes. The board icon (electron) moves about the board by creating or moving into an empty spaces (the hole). So even though it is the board piece that does the moving (the electron), equal to that, there is a requirement for having a the space to move into, which enables the game to continue working. Many board games strategies are based on eliminate ones opponents ability to move into a hole.
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