"What is Electricity?"
Electricity comprises those physical phenomena involving electric charges and their effects when at rest and when in motion. In short, it is the movement of electrons.
What are electrons?
An elementary particle which is the negatively charged constituent of ordinary matter. It is the lightest known particle or virtually weightless, but if they are in motion, they become an electric current. It is a particle which can be found in every substance.
Electrons have a single main characteristic. They have an electric charge, and all electrons have the same kind of charge. It is called a negative charge.
The electric charge around an electron acts something like a magnetic field. The behavior of positive and negative charges is very similar to the behavior of the two poles (north & south) of a magnet. All of these same negative charges do one thing: they repel each other.
In wiring conductors, billions of free electrons are safely in place in their fields. They are distributed evenly throughout the wire as shown in Fig.1.
Fig. 1. In every conductor, such as a copper wire, there are a large number of free electrons.
Direction of Electron Flow
As mentioned earlier, electrons are almost weightless, if you can get one to move, the repulsion of the like charges will make every free electron in the wire move. As illustrated in Fig.2, they will all move basically in the same direction.
Fig. 2. When the electrons are forced to move, they become a current flow and are able to perform work. No one electron moves from one end of a conductor to the other.
In order to do work, the electrons have to be in motion. Electrons do no work if they are motionless.
It doesn't matter whether the electrons move in one direction or in the other direction. They can start off in one direction, stop, reverse themselves, and vice versa. The important thing is to have them move when they are supposed to. Work is performed as long as the electrons move.
Common electron movement used in the United States and other similar countries, is the electricity that caused to flow through wires at a 60 Hz (cycles per second) frequency and 50 Hz for some other countries especially in Europe. This means the electrons flow first in one direction, then in the reverse direction, repeating this cycle 60 times or 50 times every second.
Electrical Pressure, or Voltage
Electrons can be forced to move by pushing more electrons into the wire, as in Fig 3. However, no electrons can get into the wire unless an equal number of electrons are pushed out the other end.
For instance, when you plug a lamp into a wall receptacle, electrons force their way into one wire. The electrons are moved through that wire, through the filament of the lamp, and out through the other wire.
If the filaments are broken, the electrons cannot move. The path is now open, apparently the electrons cannot travel in an incomplete circuit.
The force motivating electrons to "flow" in a wire or circuit is called voltage. Voltage is a specific measure or difference of potential between any two conductors of the circuit concerned. Common typical voltage range assigned to a circuit or system are 120/240V, 480Y/277V, 600V and according to the NEC Code, the actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.
Fig. 3. When voltage (electrical pressure) is applied to a wire, the loose electrons are packed under pressure. Note how many more electrons there are in this section of wire than there were in the previous diagrams.
Flow of Current
The amount of electric current that flows is measured in amperes (amps).
It doesn't matter which way the current flows, or if it turns around in midstream and flows in the reverse direction. The only thing that counts is the rate of flow of electrons that pass a cross section of wire, such as the section being monitored in Fig. 4.
Fig.4. The electric current flow or amperage which can be measured with an ammeter is the rate of electron flow that passes through a cross section of wire.
As the current flows, the resulting work consumes energy. The current tends to heat what ever it is moving through. Examples: If it is passing through a filament of lamp, the filament gets white hot and emits light; When it passes through the heating element of a toaster, the element gets red hot and transmits heat to the bread; Should current be passing through the field coils of a motor, a magnetic field is generated that makes the motor rotate, producing mechanical power.
The amount of current used varies accordingly as different appliances are turned on and off. This, you will pay the electric company for the amount of current flow you use from their wires or cables.
What is a Watt?
Watts are the unit of measurement for electrical power. Power is a measure of the instantaneous electrical work being done. Voltage times current equals watts. Therefore,
E = voltage;
I =current
An elementary particle which is the negatively charged constituent of ordinary matter. It is the lightest known particle or virtually weightless, but if they are in motion, they become an electric current. It is a particle which can be found in every substance.
Electrons have a single main characteristic. They have an electric charge, and all electrons have the same kind of charge. It is called a negative charge.
The electric charge around an electron acts something like a magnetic field. The behavior of positive and negative charges is very similar to the behavior of the two poles (north & south) of a magnet. All of these same negative charges do one thing: they repel each other.
In wiring conductors, billions of free electrons are safely in place in their fields. They are distributed evenly throughout the wire as shown in Fig.1.
Fig. 1. In every conductor, such as a copper wire, there are a large number of free electrons.
Direction of Electron Flow
As mentioned earlier, electrons are almost weightless, if you can get one to move, the repulsion of the like charges will make every free electron in the wire move. As illustrated in Fig.2, they will all move basically in the same direction.
Fig. 2. When the electrons are forced to move, they become a current flow and are able to perform work. No one electron moves from one end of a conductor to the other.
In order to do work, the electrons have to be in motion. Electrons do no work if they are motionless.
It doesn't matter whether the electrons move in one direction or in the other direction. They can start off in one direction, stop, reverse themselves, and vice versa. The important thing is to have them move when they are supposed to. Work is performed as long as the electrons move.
Common electron movement used in the United States and other similar countries, is the electricity that caused to flow through wires at a 60 Hz (cycles per second) frequency and 50 Hz for some other countries especially in Europe. This means the electrons flow first in one direction, then in the reverse direction, repeating this cycle 60 times or 50 times every second.
Electrical Pressure, or Voltage
Electrons can be forced to move by pushing more electrons into the wire, as in Fig 3. However, no electrons can get into the wire unless an equal number of electrons are pushed out the other end.
For instance, when you plug a lamp into a wall receptacle, electrons force their way into one wire. The electrons are moved through that wire, through the filament of the lamp, and out through the other wire.
If the filaments are broken, the electrons cannot move. The path is now open, apparently the electrons cannot travel in an incomplete circuit.
The force motivating electrons to "flow" in a wire or circuit is called voltage. Voltage is a specific measure or difference of potential between any two conductors of the circuit concerned. Common typical voltage range assigned to a circuit or system are 120/240V, 480Y/277V, 600V and according to the NEC Code, the actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.
Flow of Current
The amount of electric current that flows is measured in amperes (amps).
It doesn't matter which way the current flows, or if it turns around in midstream and flows in the reverse direction. The only thing that counts is the rate of flow of electrons that pass a cross section of wire, such as the section being monitored in Fig. 4.
As the current flows, the resulting work consumes energy. The current tends to heat what ever it is moving through. Examples: If it is passing through a filament of lamp, the filament gets white hot and emits light; When it passes through the heating element of a toaster, the element gets red hot and transmits heat to the bread; Should current be passing through the field coils of a motor, a magnetic field is generated that makes the motor rotate, producing mechanical power.
The amount of current used varies accordingly as different appliances are turned on and off. This, you will pay the electric company for the amount of current flow you use from their wires or cables.
What is a Watt?
Watts are the unit of measurement for electrical power. Power is a measure of the instantaneous electrical work being done. Voltage times current equals watts. Therefore,
E = voltage;
I =current
E x I = Power (P), in watts (W) or simply P = EI
Since a watt of power is so small, power is measured in kilowatts (KW), which are thousands of watts.
You do not, however, pay the electric company for power; you pay for energy. Energy is the amount of power used over a period of time. The common energy unit is the called the kilowatt-hour (kWh). That's the amount of energy used when a kilowatt of power is taken from the utility for 1 hour. In Fig.5 are shown a number of appliances that would use 1000W (1 kW) of power if they were all turned on at the same time.
Fig.5. If all these appliances were turned on, you would be using 100 watts of electricity. When 1000 watts of electricity is used for one hour, it is measured as a kilowatt-hour.
The wattage of an appliance is simply the amount of power needed to enable the appliance to function properly, and the kilowatt-hour reading from the electric meter lets you know how much energy you have to pay the electric company for.
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