Chapter 11

Definition: a closed path along which electrons powered by an energy source can flow

• Extra Info: There are different types of circuits, such as series circuits, and parallel circuits. Circuits contain, an energy source, conductors (wires), and usually switches and a load(/loads).
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• Related Terms:
• -Open Circuit (electric circuit with a gap in it)
• -Series Circuit (a type of circuit)
• -Parallel Circuit (a type of circuit)

Definition: a source of energy that generates an electric current through chemical reactions involving two different metals or metal compounds that are separated by a solution that is a conductor

• Extra Info: A voltaic cell has two terminals (negative and positive), called electrodes, which are made of different metals that have a different hold on electrons. The electrodes are immersed in a conducting solution or paste, called an electrolyte.
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• Related Terms:
• -Dry Cell (a type of cell)
• -Wet Cell (a type of cell)
• -Fuel Cell (a type of cell)

Definition: a connection of two or more cells

Extra Info: Batteries have two metal terminals, called electrodes, that are immersed in a conducting solution/paste (electrolyte). Chemical reactions created in the battery create electrical energy, which can flow through circuits.

• Example: An example of a battery is a 1.5V Duracell battery (the positive terminal is shown as a bump sticking out of the top).
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Related Terms:

Definition: a place on a cell (usually on the top/bottom) that must be connected to other components to form a circuit

Extra Info: Terminals are slightly different from electrodes. Electrodes are the actual metal material inside a cell/battery, while terminals are the location on the outside of the cell/battery that connect the electrodes and their energy to the rest of a circuit.

• Related Terms:
• -Electric Circuit
• -Electrode

• Fun Fact: Electrode is a Pokémon. I searched up "electrode" on Google images and this thing popped up. -_-
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Definition: a solution or paste that conducts charge

Extra Info: Electrolytes can be in a paste form, and in a liquid form. Electrolytes can be found in batteries/ cells. Electrodes are immersed in electrolyte so chemical reactions will occur.

• Related Terms:
• -Electrode
• -(Wet/ Dry) Cell
• -Battery
• -Conductor

Definition: a cell that contains an electrolyte that is in a paste form

Extra Info: Dry cells are cheaper to make and buy than wet cells, but don't last as long. Dry cells can have different voltages (e.g. 1.5V, 4.5V, 9V).

• Examples: There are different types of dry cells, such as Zinc-Carbon cells, Alkaline cells, Silver-oxide cells, and Zinc-air cells (some are better than others, for example the Alkaline cells last longer than the traditional Zinc-Carbon cells, but cost more to make).
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• Related Terms:
• -Cell
• -Battery
• -Wet Cell

Definition: a cell that contains an electrolyte that is in a liquid form

Extra Info: Wet cells generally last longer than dry cells, since they contain several compartment of electrolytes, separated by plates of metal (e.g. lead dioxide plates).

• Example: Car batteries are wet cells (usually lasting 3-5 year).
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• Related Terms:
• -Cell
• -Battery
• -Dry Cell

Definition: a cell that can only be used once

• Example: A Duracell battery.
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• Related Terms:
• -Cell
• -Secondary Cell

Definition: a cell that can be recharged

Example: A cell phone battery.

• Related Terms:
• -Cell
• -Primary Cell

• Definition: a cell that generates electricity through the chemical reactions of fuel that is stored outside of the cell
• Example:
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• Related Terms:
• -Cell
• -Dry Cell (a type of cell)
• -Wet Cell (a type of cell)
• -Solar Cell (a type of cell)

Definition: a cell that converts sunlight into electrical energy

• Example: Here is a solar cell (solar panel) in a circuit.
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• Related Terms:
• -Cell
• -Dry Cell (a type of cell)
• -Wet Cell (a type of cell)
• -Fuel Cell (a type of cell)

Definition: a place on a cell (usually on the top/bottom) that must be connected to other components to form a circuit

Extra Info: Terminals are slightly different from electrodes. Electrodes are the actual metal material inside a cell/battery, while terminals are the location on the outside of the cell/battery that connect the electrodes and their energy to the rest of a circuit.

• Related Terms:
• -Electric Circuit
• -Electrode

Definition: a control device in a circuit that can open or close, causing the circuit to be broken or complete

• Example:
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• Related Terms:
• -Open Circuit

Definition: a circuit that contains a gap or break

• Extra Info: Circuit can be intentionally broken (e.g. with the use of switches), which humans use for their convenience. 
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• Related Terms:
• -Electric Circuit
• -Switch

Definition: the rate of movement of electric charge

• Extra Info: Current is measured in amperes (amps/ A). Current stays the same throughout a series circuit, but decreases in parallel circuits when there are multiple pathways (since the electrons split up). Current is represented  by the variable, "I," in equations such as, I= V/R. Electric current can be measured using an ammeter.
• Ammeter:
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• Related Terms:
• -Ampere (A)
• -Resistance
• -Potential Difference

Definition: the quantity of charge that is equal to the charge of 6.25 x 10¹⁸ electrons

• Related Terms:
• -Ampere (A)
• -Volts (V)
• -Joules (J)

Definition: the unit of electric current, equivalent to one coulomb per second

• Related Terms:
• -Coulomb (C)
• -Current

Definition: the property of a substance that interferes with electric current and converts electrical energy to other forms of energy (e.g. heat energy)

Extra Info: Resistance of a wire depends on the length, diameter, temperature, and material of a wire. The longer, thicker, or hotter a wire is, the more resistance. Different materials have a different amount of resistance. Resistance of loads depend on how the load is made (e.g. one bulb might have a different resistance than another bulb since they are not made the same). Resistance is represented by the variable, "R," in equations such as, R= V/I.

• Related Terms:
• -Ohm (unit used to measure resistance)

Definition: a device used in an electrical circuit to decrease the current flowing through a component by a specific amount

Extra Info: Resistance in a circuit is often avoided on purpose, but sometimes a certain amount/ change in resistance is required for some devices humans have created, and thus the resistor was created.

• Related Terms:
• -Resistance (resistors increase this)
• -Ohm (unit measurement of resistance)

Definition: a resistor or any device that converts electrical energy into another form of energy (i.e. heat, motion, sound, light)

• Examples: Light bulb (heat, light), toaster (heat), television (heat, sound, light), fan (motion).
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• Related Terms:
• -Potential Difference
• -Resistance

Definition: the difference between the electric potential energy per unit of charge at two points in an electric circuit

• Extra Info: The potential difference around a circuit will always be the same as the volts the cell gives (e.g. if the battery in a circuit is 9V, then the potential difference of the circuit will be 9V, unless there is no loads). The sum of the potential difference in a series circuit equals the total potential difference, while the potential difference of each load in a parallel circuit is equal to the total potential difference. Potential difference is represented by the variable, "V," in equations such as, V= IR. Potential difference can be measured using a voltmeter.
• Voltmeter:
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• Related Terms:
• -Volts (unit used to measure potential difference)

Definition: the unit used to measure potential difference, equivalent to one joule (J) per coulomb (C)

Extra Info: If a battery is labelled "6V (6 volts)," then the potential difference of the circuit will be 6V if there is no loads.

• Related Terms:
• -Potential Difference

Definition: a diagram that uses standard symbols to represent the components in an electric circuit and what they are connected to

Extra Info: Switches are usually drawn open in these diagrams so that they are not confused with the symbol for connected wires. Circuit diagrams are usually drawn rectangularly. 

• Example of symbols (symbols may vary slightly in different circuits diagrams):
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• Example of Series Circuit Diagram:
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• Related Terms:
• -Open Circuit (a circuit with a gap in it)
• -Series Circuit (a circuit with one path)
• -Parallel Circuit (a circuit with multiple paths)

Definition: a circuit in which there is only one path for electrons to flow along

Extra Info: If one part of the circuit stops working, the whole circuit won't work.

• Example:
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• Related Terms:
• -Electric Circuit
• -Open Circuit
• -Parallel Circuit

Definition: a circuit in which there is two or more paths for electrons to flow along

Extra Info: If one part of an optional pathway (there is more than one path) of a parallel circuit stops working, only that pathway will not work. The rest of the circuit continues as usual.

• Example:
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• Related Terms:
• -Electric Circuit
• -Open Circuit
• -Series Circuit

Definition: the ratio of potential difference to current is a constant called resistance

Extra Info: There are some things that do not follow this law, such as superconductors (they have no resistance; if they do not have resistance they cannot have current or potential difference, so this law does not apply).

• Related Terms:
• -Resistance
• -Potential Difference
• -Current
• -Ohm
• -Superconductor
• -Non-Ohmic

Definition: the unit for resistance, equivalent to one volt per ampere (V/A)

Extra Info: The symbol for ohm is the Greek symbol, omega.

• Related Terms:
• -Resistance
• -Ampere (A)

Definition: a material which allows electric charge to flow through with no resistance

Extra Info: Superconductors do not follow Ohm's Law.

Example: Mercury.

• Related Terms:
• -Conductor
• -Current
• -Resistance
• -Ohm's Law

Definition: not following Ohm's Law

Example: Superconductors (e.g. Mercury)

• Related Terms:
• -Ohm's Law
• -Superconductor

Definition: loads that are one after another in a series circuit

Extra Info: The current in a series circuit will be the same throughout (if it's 0.6A after leaving the battery, it will also be 0.6A after exiting the loads) ₍I_T = I₁ = I₂ = I₃). The potential difference splits up between loads in series (if loads are identical, energy will split up evenly) (V_T = V₁ + V₂ + V₃). Adding more loads is similar to adding more wire (it increases the resistance, so more loads= more resistance), and the total sum of the resistance of the loads is equal to the total resistance of the whole circuit. Adding more loads in series will decrease the energy each load gets, since the energy has to be split (R_T = R₁ + R₂ + R₃).

Picture: Refer to picture for "Series Circuit."

• Related Terms:
• -Current
• -Potential Difference
• -Resistance
• -Series Circuit
• -Loads

Definition: loads in a circuit that are parallel to each other (each has its own path in the parallel circuit)

Extra Info: The current will decrease when there is multiple paths, because the electrons flowing through the wire will split up (some will go down one path, some will go down another) (I_T = I₁ + I₂ + I₃). If all of the loads are identical and there is the same number of loads on each path, the current will split evenly. The potential difference is the same down each path because the electrons are splitting up, but the energy that they are carrying is the same (V_T = V₁ = V₂ = V₃). The resistance will decrease because the electrons will have more paths to travel through so there is less collision from being crowded (R_T < R₁ or R₂ or R₃).

Picture: Refer to picture for "Parallel Circuit."

• Related Terms:
• -Current
• -Potential Difference
• -Resistance
• -Parallel Circuit
• -Loads