Electricity Basics

Electricity, as a form of energy, has a lot of advantages: it is silent and clean, and it can be converted into most other forms of energy with very high efficiency.

Its major downside, the difficulty to store it, can be handled with batteries, although they are expensive.

Electrons can travel through wires and cables like water can travel through a pipe. A source of electricity, like an power outlet or a battery, has two metallic contacts (called poles on a battery). The electrons travel from one contact through the appliance, powering it, and then back into the other contact. This is what we call the electric circuit.

The electrons move, because they are being “pushed” by a force called electric tension, also called voltage, because the used unit is Volts (V).

The measure for how many electrons are crossing the wire is called electric current, or amperage, as the used unit is Ampere (A).

1 Ampere means basically that 6250 quadrillion electrons pass a point in the cable per second. Since “6250 quadrillion electrons per second” is a bit complicated as a unit, the unit Ampere was introduced.

If we want to know, how much power (watt) an electric device uses, the easiest thing is to look at its sticker with technical information, often on the bottom. Sometimes the power consumption in written in watts. If it is not, it can easily be calculated by multiplying the amperage with the voltage:

Example: If a toaster that plugs into a 120 V AC outlet, takes 6.5 A of current, the power consumption is 780 W.

Electric devices need a certain voltage to operate. Too low, or too high voltage can damage the device, or it simply won't work. Fortunately, we don't have to think about his too much in our daily lives: There are standardized systems, all with their own outlets and plugs:

Your regular old power outlet. The voltage is 120 V (with an alternating current = AC). The maximum current is usually 15 A, so the maximum power from a household outlet you can get is 120 V x 15 A = 1800 W.

You need to be a licensed electrician in order to work with 120 V (e.g., installing outlets in a cabin), since it is dangerous and can kill you!

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Used to charge small electronic devices, like your phone. Usually the voltage is 5 V, and the maximum current is 2 A (= 10 W of power). Most modern phones and even laptops can charge faster, thanks to technologies like USB-C Power Delivery.

The cigarette lighter plug in your car provides 12 V (direct current = DC). Off-grid solar PV systems also often use 12 V DC. Other than 120 V AC, it is safe to work with, the voltage is not high enough to seriously hurt you.

You can transform 12 V DC into 120 V AC with the help of an inverter.