Electricity Chapter 11

• A closed path along which electrons that are powered by an energy source can flow.
• This can take the form of a circuit board, loads wired together, the wires in your house, and even something as large as the power grid.

• A source of energy that generates an electric current by chemical reactions involving two different metals or metal compounds separated by a solution that is a conductor.
• Some common types would be: Zinc-Carbon, Alkaline, Lead-Acid, Silver-Oxide, etc.

• A connection of two or more cells.
• When you place two AA "Batteries" (which are really cells) in a flashlight you make a battery.

• One of two metal terminals in a cell or battery.
• They must be made of different metals with different holds onto electrons so the electrons know which way to flow.

• A solution or paste that conducts charge.
• The electrolyte separates the two electrodes and the chemical reaction that takes place to move electrons happens within the electrolyte.

• A cell that contains an electrolyte that is a paste.
• Some common dry cells would be Zinc-carbon and Alkaline.

• A cell that contains a liquid electrolyte.
• An example would be a lead-acid battery.

• A cell that can only be used once.
• Some examples would be Zinc-Carbon and Alkaline.

• A cell that can be recharged.
• Some common types would be lead-acid and lithium-ion.

• A cell that generates electricity through the chemical reactions of fuel that is stored outside the fuel cell.
• An example would be a hydrogen fuel cell that combines hydrogen and oxygen to make water, heat, and electricity.

A cell that converts sunlight into electrical energy.

• The location on a cell that must be connected to other components to form a circuit.
• Both the positive terminal and negative terminal must be connected to the circuit to complete it.
• Electrons flow from the negative terminal to the positive terminal.

• A control device that can complete or break the circuit to which it is connected.
• This is useful because circuits don't have to be on all the time if you have a switch.

• A circuit that contains a gap or break.
• An open circuit can not function since there is no complete path for electrons to travel along.
• Hitting a switch or button on a lamp or TV can open or close a circuit.

• The rate of movement of electric charge (flow of electrons).
• An analogy would be to think of how many m³ 
• of water flow by in a river per second.

The quantity of charge that is equal to the charge of 6.25 * 10¹⁸ electrons.

• The unit of electric current, equivalent to one coulomb per second. 
• An ammeter measures the amount of current in one location of a circuit in amperes.

• The property of a substance that hinders electric current and converts electrical energy to other forms of energy.
• Some materials have lower or higher resistances than other materials.
• Materials with lower resistances are conductors while materials with very high resistances are insulators.

• A devices used in an electric circuit to decrease the current through a component by a specific amount.
• These are useful to ensure that components in a circuit don't get too much energy and break.

• A resistor or any other device that transforms electrical energy into heat, motion, sound, light, or other forms of energy.
• Some examples would be: a speaker, a light a bulb, a motor, a stove, etc.

The difference between the electric potential energy per unit of charge at two points in a circuit.

• The unit for potential difference, equivalent to one joule (J) per coulomb (C).
• The equation to find potential difference is:
• potential difference = difference in potential energy (J) / charge (C)

• A diagram that uses standard symbols to represent the components in an electric circuit and their connections. 
• Some standard symbols are that two parallel lines of different length represent a cell, straight lines are connecting wires, and a switch is a portion of the wire that looks swivelled open.
• 

• A circuit in which there is only one path along which electrons can flow.
• If a series circuit is broken at any point then the whole circuit will stop functioning.

• A circuit in which there is more than one path along which electrons can flow.
• Parallel circuits can be broken and any path not affected by the break can still function.

• The ratio of potential difference to current is a constant called resistance.
• The equation is written as V=IR
• Thus the more resistance in a circuit, the less current since they is more resistance to the movement of electrons and the movement of electrons is current.

• The unit for resistance, equivalent to one volt per ampere (V/A).
• If you substitute in potential difference and current measurements into the equation V=IR you can find the resistance in ohms.
• All loads in a circuit increase the resistance of a circuit.

• A material through which electric charge can flow with no resistance.
• An example of a superconductor is when the wires in the CERN supercollider are cooled to a few degrees above zero with liquid helium.

• Not following Ohm's law.
• An incandescent light bulb filament is non-ohmic since the filament increases in temperature which increases the resistance and produces a non-ohmic energy curve.

• In a series circuit the potential difference across the cell must equal the sum of all the potential differences across all of the loads.
• V_T = V₁ + V₂ + V₃ + ...
• The current of through the battery is equal to the current through all the loads.
• I_T = I₁ = I₂ = I₃ = ...

• In a parallel circuit the potential difference across the cell is equal to the potential differences across of the loads.
• V_T = V₁ = V^₂ = V₃ = ...
• The current total current must be equal to the sum of all the currents through all the paths.
• I_T = I₁ + I₂ + I₃ + ...