|
What is electricity and how is it different from electronics?
Electricity is the flow of electrons from one place to another. While this explanation is somewhat simplistic, for the purposes of our discussion at present, that definition will do. Again simplistically, think of electronics as the use of tubes (old tech) and semiconductors (current tech) to manipulate the parameters of electricity so that it will do what we want.
Think of it this way, the power lines coming to your house carry electricity, as does the wiring in your house. Once the electricity gets to a component, such as your television, it is then modified by electronics to provide a picture and sound.
Electricity has many different parameters, but at its most basic there are two for DC and three for AC, (these acronyms will be explained later). Electricity has voltage and it has current. Voltage is potential energy and is controlled by the supplier. When National Grid makes the electricity that comes to your house they set the voltage they want to send out at the generator itself by controlling the size or strength of the magnetic field (again, to be explained a little later). The current is determined by the user. The more stuff you turn on, the higher the flow of current that comes into your house.
There are two types of electricity, AC (alternating current) and DC (direct current). Alternating current is made, usually, by generators whereas DC is made, usually, by batteries. If you were to put a multimeter set to read voltage to the terminals on, for example, a car battery, you would read a constant 12 volts. This is the DC put out by the battery, it doesn't change other than voltage will decrease as power in the battery is used up by a load. AC comes from generators which turn and therefore the voltage actually goes from zero, up to the set voltage, down through zero to the negative of the set voltage and back up in a sine wave. The reason for this is the way that a generator makes electricity.
To make AC current or electricity takes three things, a magnetic field, a current carrying conductor and relative motion between the two. As such, if you were to take a magnet off your fridge and wave it around in the area of a piece of copper wire, you would actually be generating and electrical current in that wire. What the generators at the power plant do or have is a huge winding of copper wire wrapped around a shaft that is turned by a turbine or a diesel engine or some other motive force. In the casing of the generator is another set of windings of copper wire. When the unit is started up, once warmed and up to its operating speed, we "flash the field" in the moving windings, that is to say we create a self sustaining, controllable magnetic field in those moving windings. Then, as the magnetic field "cuts across" the stationary windings in the generator casing, a current is induced/electricity is created. AC Power has a 3rd parameter, as stated above, and that is called frequency. Frequency is the number of cycles of that sine wave per second and is measured in Hertz (Hz). In the United States we run on 60 Hz power. In Great Britain they use 50 Hz. The frequency is controlled by the speed of the generator. The voltage is controlled by controlling the "size" or strength of the magnetic field. Current, again, is controlled by the load placed on the system by the users.
|
Login
Register
FAQ
Search
