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Endesa - Electricity, Gas, People

Volts, Watts and amps: What are they and how do they differ?

Published on May 21, 2018

Three different units of measurement but so close that they can be confusing. We'll explain what the volts, Watts and amps are. What they are for and why they should be important to you.

The volts, Watts and amps are three basic concepts for understanding electricity, but it is normal for us to quickly forget the lessons of the Institute and we don't even know what they are or how they affect our daily lives.

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.

Volts: The voltage of a battery

When the electrons move between two points through a conductive material (e.g. a cable) they generate electric current.

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.

The volts measure the energy potential that a given circuit can provide.

Why do/should you care? 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 230 volts. When you connect a device to that socket, the electrons will start to fall down that slope, pushed by the voltage and generate an electric current with voltage of + 230 V.

Other voltages in your daily life can be those of an electric battery (+ 1.5 volts), your car's battery (+ 12.5 volts) or one of your neurons (-75 millivolts).

Amps: The capacity of the batteries

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?) have moved between one point and another for a space of time.

The amp-hour (Ah symbol) expresses how much power can be circulated by a given circuit for one hour. It is used to measure the capacity of the electric batteries. For example: A 10 Ah battery can provide a 10 amp current for one hour. The more amperes, the more electrons will flow through the circuit (or more balls fall down the slope).

Why should you care? Because you depend on devices that work for you only as much as your amps allow. For example: The battery of your mobile phone is around 3 ampere-hours, so it will run out as soon as it exceeds this limit.

Amps are used to express how much the battery can hold on a mobile phone before it is exhausted.

Watts: The power of your appliances

Watts measure the power, i.e. the energy supplied in a given time space.

Volts (V) x amps (A) = Watts (W)

Continuing with the analogy of the ball and the slope, the Watts (W) are all the energy provided by all the balls (amps) when traversing the slope (volts).

El símbol dels watts és W.

Why should you care? The Watts you need to find out what the power is that you have contracted in your home and appliances. Or in its Watt-hour variant (energy supplied for one hour) to know the consumption of your appliances. These issues end up having a direct effect on your light bill.

Another analogy for volts, watts and amps

If it's still not clear, or if the analogy of the ball and the slope has not convinced you, we propose that you think of a river:

  • The voltage (measured in volts) would be the orography, the difference in height that makes the river flow from the mountains to the sea. Without the height difference, the water would be stagnant. The same goes for electricity: without voltage there is no current.
  • Amperes (intensity) would be the amount of liters of water coming down the river. Obviously, it is essential to decide if you want to measure it per minute, per day... or per hour with the amp-hour.
  • The watts (the power) would be the energy that carries the current, which depends on both the orography and the water flow. For this river to generate electricity through a hydroelectric power plant, it will be worth assessing whether the orography and the flow favor the generation of energy. A lot of voltage and intensity will give rise to a great power.

In a river ,the Watts would express the generated energy when an amount of water (Amps) descends from a certain height (volts).