Section 1 & 2 - Electrical Principles & Technologies

Static Electricity

Static Electricity

Stationary electric charge (Things with static electricity are lightning bolts & the shock you get from a metal object)

Electrical Energy

The energy of charged particles. This energy is transferred when electrons travel from place to place

Electrical Discharge

The sudden transfer of electrical charge from one object to another. (indicated by a spark)

Electrical Current

The steady flow of charged particles

Van De Graaff Generator

A device that builds up static charge. (uses a rubber belt that rubs on a piece of metal and transfers the charge to a sphere. The charge builds up on the sphere and transfers to you when you touch it)

Proton

Positively charged particle in the nucleus of an atom

Electron

Invisible negatively charged particle that orbits the nucleus of an atom

Neutron

A particle that has both a (+) and (-) charge

Neutral

Description of an object that has equal amounts of positive and negative charges

Charge Separation

Concentration of like charges in specific areas of a neutral object, caused by the approach of a charged object

The Laws of Electrical Charges

Opposite charges attract each other.

Like charges repel each other

Electrical current

The steady flow of charged particles. It flows continuously unlike static electricity that builds up & discharges.

Ammeter

Meter used to measure electrical current in amperes

Amperes (A) - (Amps)

The unit used to measure the rate of the flows in an electrical current.

Circuits

Paths that control the flow of electricity. It manipulates the path that electricity travels on & where it is to be received.

Electrical Energy and Voltage

The energy carried by charged particles, while Voltage is a measure of how much electrical energy each charged particle carries.

Measuring Voltage

You use a voltmeter, which is a device that receives current in order to see how much there is. Voltage is measured in “volts” (V), or “millivolts” (1/1000)

Conductor

A material that electric charge can move through easily

Load

The device in a circuit that converts electrical energy to another form of energy

Voltage (V) - (Volts)

A measure of how much electrical energy a charged particle carries

Voltmeter

An instrument for measuring potential difference in volts

How does current electricity differ from static electricity?

Current electricity is the steady flow of charged particles which flows continuously. However, static electricity builds up & discharges, meaning it changes constantly.

Dangers of electrical shock

High amounts of voltage & amperage can become unsafe. Shocks from high voltage & amperage can cause a painful shock & loss of muscle control.

Plugs, Fuses, and Breakers

All of these devices interrupt the flow of electricity if too much flows through. This allows for wires to cool & to avoid short circuits which can end up doing great harm to you.

Dangers of Lightning

Lightning is static charge & so getting struck by it can kill you due to the mass of electron exchange happening. To avoid this, lightning rods have been on top of buildings to attract the electricity there rather than on a person.

Short Circuit

Accidental low-resistance connection between two points in a circuit, often causing excess current to flow

Insulators

Substance that strongly resists the flow of electricity

Fuses

Thin piece of metal that melts to break an electrical circuit when excess current flow occurs

Circuit Breakers

Special wire that heats up and turns off switch when excess current flows through an electrical circuit

What is meant by a “ground wire”?

The leftover of electrical current being transferred to the ground. When a lightning strike uses a human as a vessel to transfer electricity, that electricity gets sent into the ground because of attraction.

Lightning Rod

Avoid the possibility of lightning striking a person & causing harm. They are put on top of buildings (where lightning is attracted to) & they make it so that the strike lands on the insulated rod & balanced out the number of electrons which come from the strike.

Dry Cell

A cell that has its electrolyte in the form of a paste. They are sealed to avoid any chemicals from inside spilling out.

Wet Cell

An electrochemical primary cell having a liquid electrolyte. These liquids are mostly acids that transport electricity.

Rechargeable cells

Cells that produce electricity through a chemical reaction. This reaction can be reversed using an external source to run electricity back through the cell.

Electroplating

The use of electricity to coat a thin layer of metal onto an object.

Electrolysis

The decomposition of a substance by an electric current

Electrolyte

Liquid or paste that conducts electricity because it contains ions

Electrode

Conductor through which electric current enters or leaves a device or material

Resistors

Devices that allow electrons to pass through a circuit but keep some resistance on it.

Resistance (Ohm’s) - (Ω/I)

The measure of how difficult it is for electrons to flow through a substance

Switches

Turn the circuit on and off by closing and opening the circuit.

Superconductor

Perfect conductor; substance with no resistance to electron flow

Variable Resistor

Resistor whose resistance can be changed by adjusting the portion of the resistor the current travels through

Rheostat

Continuously variable resistor used to regulate electric current

Ohm's Law

A law that states that as long as temperature is constant, that the resistance of a conductor remains constant. This current is then directly proportional to the voltage applied.

What is Ohm’s law measured:

Using 3 equations: R = V/I or I = V/R or V = IR

Millivoltmeter

An instrument used to measure small voltages

Galvanometer

Device for detecting and measuring small electric currents

Electrochemical cell

Package of chemicals designed to produce small amounts of electricity (produces electricity from chemical reactions)

Schematic

diagram using standardized symbols to show the components and connections in a circuit

Series Circuit

Circuit in which there is only a single pathway for the current

Parallel Circuit

Circuit in which the current can flow in two or more paths

Transistors

Device usually with three layers arranged such that a small voltage through the middle layer controls a current between the outer layers, allowing the device to act as a switch or amplifier

Microcircuits

Circuit made up of miniaturized components, especially an integrated circuit