It could hit a bear, it could bounce off rocks, all kinds of things, so that's a mass rolling down a hill. Now if I draw, this is a way to think about voltage, think about voltage as being another mountaintop, and this time we'll put a battery in here. This is our battery, this is what a battery does for us, it actually builds our mountain. The battery actually delivers electrons to the top of the hill, so here's an electron coming out of the battery terminal, the negative battery terminal.
And if I release this, it is going to roll down the hill. And eventually it's going to return to the bottom side of the battery. But the same thing, this is the image you have in your head when we hook up a circuit. Along the way I could put in different circuit components like resistors or capacitors or anything like that, and I could make this electron do work and bump into things as it goes down. So, the amount of voltage here is proportional to the height of this mountain. A high voltage is a high mountain and a low voltage is a low mountain.
The electrons are pushed out the top by the battery and roll down to the bottom doing work along the way, and this is where we do our circuit design.
That's what we're doing over here, we buy batteries and we do our circuit design and study over here. So this is a pretty good analogy for thinking about voltage as you begin to build your circuits. When the circuit is composed of metallic materials, the moving charged particles are electrons. The battery pushes electrons in the circuit away from its negative terminal and pulls them towards the positive terminal like charges repel, unlike charges attract; see the focus idea Electrostatics — A non-contact force.
The chemical reactions in a battery involve the movement of charged particles inside the battery; this results in an excess of negative charged particles at one battery terminal the negative terminal and an excess of positive charged particles at the other terminal.
An electron at the negative terminal will be pushed away from this terminal and pulled towards the positive terminal if the battery is connected into a circuit.
The excess charges on the battery terminals create pushes and pulls simultaneously on electrons all around the circuit. This pushing and pulling is an example of forces acting at a distance; scientists use the term electric field see the focus idea Forces without contact to describe these pushes and pulls. Change at any point in a circuit affects the whole circuit. Because of their position in the electric field electrons in the circuit have electric potential energy.
As electrons move in the circuit, the electric potential energy is transformed into low grade heat and whatever useful forms of energy the circuit devices are designed for see the focus idea Is energy conserved or running out?
There is a difference in electric potential energy for each charge between any pair of points in a circuit. This is almost always abbreviated to potential difference. An alternative label for potential difference is voltage, a label that comes from our measuring this in volts. Potential difference and electric field are intertwined.
If there is a potential difference in a circuit, then there is an electric field; if there is an electric field in a circuit, then there are forces acting on charged particles in the circuit. Therefore, if there is a voltage in a circuit, then there might be a current the circuit needs to be complete before there is a current. Since voltage is the difference in electric potential energy per charge, we should measure it in terms of energy per charge — and we do.
Explore the relationships between ideas about voltage in the Concept Development Maps — Electricity and Magnetism. It's not just a theory taken from an old manual. It is real life: when the car does not start or when the light goes out in your house.
We tell you in a short and simple way what the volts, watts and amps are. Get interested in what you care about. When the electrons move between two points through a conductive material e. Electrons can't resist this trip, just like when you drop a ball on a slope. The law of gravity forcing the ball electrons to roll is the voltage or electrical voltage.
When the ball is at any point on that slope, all the descent that lies ahead is its potential energy. The volts symbol V measure the different potential energy that exists between one point and the other. The volts are thus named in honor of Alessandro Volta, the inventor of the battery. You should care because your life is full of voltages.
If you look at any plug you will see two holes. Imagine that one of them is the highest point of the slope and the other is the end. Between the two points there is a difference of volts. Amperes measure the intensity of an electric current. Continuing with the analogy of the ball and the slope, the amps serve to tell us the amount of energy how many balls? The amp-hour Ah symbol expresses how much power can be circulated by a given circuit for one hour.
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