Every electric circuit, no matter where it is or how large or little it is, has four fundamental components: an energy source (alternating current or direct current), a conductor (wire), an electrical load (device), and at least one controller (switch). The energy source provides power to the circuit. The conductor carries the power from the source to the load. The controller allows some action to be taken on the circuit (such as turning off the water when you aren't using it). The load uses up the power provided by the circuit.
The first part of a circuit is called the "line" because it connects the energy source to the rest of the circuit. The line can be a wire that passes directly from the source to the load, or it can be through a switch first. No matter what type of line there is more than one thing that could go wrong with it so it's important to know how to test it properly.
The second part of the circuit is called the "grounding system" because it gives the load a safe place to send its electricity back to earth. Grounding systems include any metal objects in your home or office building that will ground out dangerous voltage levels. These can include water pipes, gas lines, sewage lines, phone cables, and floor joists.
The third part of the circuit is called the "electrical load".
Consider what occurs when you turn on a light in a room. You have just created a circuit between the light bulb and the wall outlet, which is called a "circuit path." The electricity from the outlet flows through the wire that connects it to the wall panel, then into the light fixture, and finally out through the metal parts of the socket into the environment. If someone were to touch these parts while the light is on, they would get a small shock.
The key word here is "flow." Electricity can only flow through a conductor. That means a wire from your power source all the way down to your light bulb is necessary for a circuit to be completed. A single piece of wire is called a "path." It can be any length but must connect the same location of each component back to itself or another connection point.
A circuit can also have more than one "path" to the same destination. For example, if you had two separate wires running from your power source to your light bulb, they would be independent paths and could carry different amounts of current without being damaged. This would be useful if you wanted to control several lights from one switch or if one of the wires was live and needed to be separated from the other.
Every electric circuit contains at least two components: a voltage source and a conductor. They may also include additional components like as light bulbs and switches, as seen in the basic circuit depicted in the picture below. This basic circuit's voltage source is a battery. It provides electricity to make the lights work. The conductor is made of copper wires that connect the lights to the battery using metal connectors called plugs.
In any electric circuit, electricity must be able to flow from the voltage source through the conductor to each light bulb. A physical barrier can block this flow of current, so all circuits contain some type of opening for the cables feeding into the wall box or fixture housing. These openings are typically large enough for a wire to pass through, but not much larger. Modern wiring methods use special tools to help cut holes in the cover plates for wiring outlets on an interior wall surface. If these tools are not used, electricians often use a pen knife to cut around the perimeter of the hole before inserting the cable into the hole.
Conductors are usually thin strands of metal, like copper or silver. They may be single wires or they may be in a bundle with other wires. Electric circuits need conductors to transmit power from one place to another. So every circuit includes at least two conductors: one from the voltage source to the first connection point, and another from there to the second connection point and finally to the light bulb.