Current and Voltage
We’ve all used electrical devices we’ve charged our phone turned on light switches.
But what is electricity really?
I’ve had students tell me electricity is the stuff running in the wall
Or electricity is you know… juice.
Eventually someone describes electricity as the flow of electrons. And that’s correct… sort of.
Electricity is a lot like Geometry, Trigonometry, History, Chemistry. Do you see the connection? These are all topics of study and electricity is the study of the movement of electrons.
So then what IS electricity? You know … the stuff that runs in the walls. To answer that question we need to look more closely at its two separate components. To understand this more completely let’s look at something I remember from the town I grew up in Odessa TX the hottest flattest place on earth. We had these all around the city. Do you know what they are?
They’re water towers. Water is stored in the top of these towers are used to supply water to the city. But why does water need to be stored in towers instead of in a tank on the ground? We all know water runs downhill. This tendency to run downhill creates pressure that forces the water through the pipes and into your home. We can look at electricity the way we used to look at water and pipes. It takes pressure to push water through the pipes just like it takes electrical pressure to push electrons through wires. This electrical pressure we call voltage. The flow of the water in the pipes is similar to the way electrons flow through wires. Just as pressure is needed to move water through the pipes in a city, Voltage is required to move electrons or Current through a wire. These two electrical components are linked and bound together in our study of electricity.
Voltage is “Electrical Pressure” and has units of Volts (abrev. V). The symbol we use to designate for Voltage is ‘V’.
Current is the “Flow of Electrons” and has the units of Amps (abrev. A or a). The symbol used is ‘I’.
Look at this label found on a small wall power supply. The power supply is taking AC power in from the wall outlet and converting it to a DC power. Notice that both the Input and the Output are described with Voltage (V) and Current (A). This is just one way the electricity we use every day is quantified using the terms of Voltage and Current. Once we can put numbers to this invisible and seemingly intangible “stuff” we can begin to understand it better and predict how it can be used.
Look around your home at the things that use electricity. Can you find evidence of Voltage and Current in the labels on the machines?