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Electric circuit
A closed path along which electrons that are powered by an energy source can flow.
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Voltaic cell
A source of energy that generates and electric current by chemical reactions involving to different metals or metal compounds separated by a solution that is a conductor.
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Battery
A connection of two or more cells.
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Electrode
One or two of the metal terminals in a cell or battery.
The breakdown of an electrode is one factor that can limit the life of the cell.
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Electrolyte
A solution or paste that conducts charge.
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Dry cell
A cell that contains an electrolyte that is a paste.
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wet cell
A cell that contains a liquid electrolyte.
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primary cell
A cell that can be used only once.
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Secondary cell
A cell that can be recharged.
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Fuel cell
A cell that generates electricity through the chemical reactions of fuel that is stored outside the cell.
- Hydrogen fuel cell combines hydrogen that is stored in a tank or cartridge with oxygen from the air
- By-products are heat and water
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Solar cell
A device that converts solar radiation into electricity.
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Terminal
A point of connection for closing an electric circuit.
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Switch
A switch is a control device. It is a conductor that can complete or break the circuit it is . connected to.
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Open circiut
Electrons do not flow through any part of a circuit where there is a gap or break. Opening a switch creates a gap, and any device that is connected to the switch will stop working. An open circuit is one in which there is a gap or break in the circuit.
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Electric current
Electric current refers to the rate of movement of electric charge. In an electric circuit, the current is due to the flow of electrons.
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Coulomb (C)
The unit of electric charge is the coulomb and one coulomb (C) is the quantity of charge that is equal to the charge of 6.25 x 1018 electrons.
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Ampere (A)
The unit of electric current is the ampere (A). A current of 1.0 A in a circuit means that 1.0 C of charge passes through a given point in a circuit in a second. Electric current is measured using an ammeter.
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Electrical resistance
The free electrons in a solid, move when an electric field is produced by a cell. The electrons do not get very far before colliding with ions or other electrons in a solid. The collisions interfere with the flow of electrons. Electrical resistance is a property of substance that hinder the electric current and converts electrical energy to other forms of energy.
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Resistor
A resistor is used to decrease the current by specific amount.Metals have a lower resistance than non-metals.
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Load
When electrons collide with metal ions, some energy is converted into heat. A load is a resistor or any other device that transforms electric energy into heat, motion, sound, or light.
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Potential difference (voltage)
The voltage of a cell is related to the amount of work that is done on each coulomb of charge that moves between the terminals of the cell.
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Volt
V=1 J/C
A cell marked 1.5 V will do 1.5 J of work moving a coulomb of electrons from the negative terminal, through the circuit, and to the positive terminal.
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Circuit diagram
A diagram that uses standard symbols to represent the components in an electric circuit and their connections.
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Series circuit
A circuit in which there is only one path along which electrons can flow.
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Parallel circuit
A circuit in which there is more than one path along which electrons can flow.
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Ohm's law
The ratio of potential difference to current is a constant called resistance.
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Ohm (Ω)
Resistance is measured in ohms.
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Superconductor
A conductor in which there is no resistance.
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Non-ohmic
Something that doesn't obey ohm's law.
Ex. A light bulb doesn't obey ohm's law because the greater the resistance the larger the current is.
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Loads in series
Loads right after one another in a series circuit.
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Loads in parallel
Loads behind after one another in a parallel circuit.
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