Unit 10 Electricity

Difference between fuse and GFCI?

-A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. -Its basic function is to detect a fault condition and interrupt current flow. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. -Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city

Parallel Circuit

-A parallel circuit is a closed circuit in which the current divides into two or more paths before recombining to complete the circuit. -Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents.

Series Circuit

-A series circuit is a closed circuit in which the current follows one path, as opposed to a parallel circuit where the circuit is divided into two or more paths. -In a series circuit, the current through each load is the same and the total voltage across the circuit is the sum of the voltages across each load.

Closed Circuits

-An electric circuit through which current can flow in an uninterrupted path.

Insulators

-An electrical insulator is a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field. -The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors

Electrical Flow

-Electric current is defined as the rate at which charge flows through a surface (the cross section of a wire, for example). -The phrase "current through a toaster" surely refers to the flow of electrons through the heating element and not the flow of slices of bread through the slots.

How is the periodic table organized

-Elements are arranged in order of increasing atomic number atomic number: The number of protons in an atomic nucleus; it indicates the position of an element in the periodic table. The number of protons in the nucleus of an atom.

Electrical Resistance

-Resistance is an electrical quantity that measures how the device or material reduces the electric current flow through it. The resistance is measured in units of ohms (Ω). -If we make an analogy to water flow in pipes, the resistance is bigger when the pipe is thinner, so the water flow is decreased

Voltage

-Voltage is electric potential energy per unit charge, measured in joules per coulomb ( = volts). -It is often referred to as "electric potential", which then must be distinguished from electric potential energy by noting that the "potential" is a "per-unit-charge" quantity.

Ground Fault Circuit Interrupter

-in an outlet, there are two vertical slots and then a round hole centered below them. ----The left slot is slightly larger than the right. The left slot is called "neutral," ----the right slot is called "hot" and the hole below them is called "ground." -If an appliance is working properly, all electricity that the appliance uses will flow from hot to neutral. A GFCI monitors the amount of current flowing from hot to neutral. If there is any imbalance, it trips the circuit. It is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second. EXAMPLE: So let's say you are outside with your power drill and it is raining. You are standing on the ground, and since the drill is wet there is a path from the hot wire inside the drill through you to ground (see How Power Distribution Grids Work for details on grounding). If electricity flows from hot to ground through you, it could be fatal. The GFCI can sense the current flowing through you because not all of the current is flowing from hot to neutral as it expects -- some of it is flowing through you to ground. As soon as the GFCI senses that, it trips the circuit and cuts off the electricity.

How to tell if an element is an insulator or conductor?

-octet rule: basically states in order for an electron to be stable it must contain 8 valence electrons. (this rule also factors in when determining what qualification to classify an element in) -Its simple good conductors CONDUCT electrcity, and they contain unstable electrons(less than 8), such as a metal -Good insulators contain 8 electrons which mean they are stable(noble gasses group 18). Insulators can't be easily transported from one atom to another and nonmetals make good insulators.

Capacitors

A capacitor is a device for storing charge, made up of two parallel plates with a space between them. The plates have an equal and opposite charge on them, creating a potential difference between the plates. A capacitor can be made of conductors of any shape, but the parallel-plate capacitor is the most common kind.

Transformers

A device used to transfer electric energy from one circuit to another, especially a pair of multiply wound, inductively coupled wire coils that effect such a transfer with a change in voltage, current, phase, or other electric characteristic.

Fuse

A fuse is a small, thin conductor designed to melt and separate into two pieces for the purpose of breaking a circuit in the event of excessive current. A circuit breaker is a specially designed switch that automatically opens to interrupt circuit current in the event of an overcurrent condition.

an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.

ALternating Current

Open Circuits

An electric circuit in which the normal path of current has been interrupted, either by the disconnection of one part of its conducting pathway from another, or by the intervention of an electric component, such as a transistor. Compare closed circuit.

3 Types of Charging

Contact Induction: the act or process by which an electric or magnetic effect is produced in an electrical conductor or magnetizable body when it is exposed to the influence or variation of a field of force. Polarization: property of certain electromagnetic radiations in which the direction and magnitude of the vibrating electric field are related in a specified way. Light waves are transverse: that is, the vibrating electric vector associated with each wave is perpendicular to the direction of propagation.

an electric current flowing in one direction only.

Direct Current

Grounding

Grounding is the process of removing the excess charge on an object by means of the transfer of electrons between it and another object of substantial size. When a charged object is grounded, the excess charge is balanced by the transfer of electrons between the charged object and a ground.

Lightening

Lightning is the result of the build up of electrostatic charge in clouds. Positive and negative charges separate, negative usually towards the bottom of the cloud, while positive goes to the top.

Conductors

a conductor is an object or type of material that allows the flow of an electrical current in one or more directions. Materials made of metal are common electrical conductors

Batteries

a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode.

Coulomb's Law

the force of attraction or repulsion acting along a straight line between two electric charges is directly proportional to the product of the charges and inversely to the square of the distance between them.