Download 1 Alternating Current (AC) Current that constantly and rapidly

ELECTRONICS GLOSSARY
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Alternating Current
(AC)
Current that constantly and rapidly alternates direction in a circuit, from + to -. The current we get in the grid to
our homes is AC. (cf DC).
A device for measuring current. Ammeters are connected in series with the component, e.g. a globe, whose
current we want to measure.
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Ammeter
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Amps (short for
amperes)
Unit of electric current (A). 1A = 1 Coulomb per second = 6.25 x 1018 electrons per second.
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Capacitor
An electronic device that can be charged and store an electric charge.
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Chip as in microchip
Miniature semi-conductor (e.g. silicon), which contains a circuit containing transistors. Chips are used in
computers.
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Coulomb
Unit of charge; one coulomb is equal to the total charge of 6.25 x 10
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Diode
Electronic device, which allows current flow in one direction only.
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Direct Current (DC)
Current that always flows in the same direction in a circuit, as we get from a battery or a DC power pack, as we
have in the lab.
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Electric Current
Flow of charged particles through conducting circuit.
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Electricity
The energy that results from the movement of charged particles.
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Electronics
Study of, and application of electricity in, controlling devices from transistors to computers.
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Joule
Unit of measurement for work and all forms of energy (J).
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Light dependent
resistor (LDR)
Resistor with a resistance value which alters with light intensity.
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Motor
A device for producing mechanical (usually kinetic) energy form a power source.
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Ohm
Unit of electrical resistance
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Ohm’s Law
States that in a metallic conductor the ratio of voltage to current is constant; the constant is called the
resistance. Formula: V = IR.
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Parallel Circuits
A circuit in which there are alternative paths for electricity to flow
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Potential difference
(Voltage)
Electrical energy lost across a component or gained across a cell; measured in volts (V).
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Power
How much energy something uses; measured in watts (W) or kilowatts (kW).
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Rectifier
Electrical device that transforms alternating into direct current as you find in a battery charger. A rectifier would
have some form of diode device which allows only current in one direction.
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Relay
A device that allows one circuit to control another circuit without there being an electrical connection between
them. This allows a relatively low powered circuit to control a circuit with a high current. The relay we use in our
circuit is actually an electromechanical relay which uses the magnetic force of a current to close a switch.
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Resistor
A component which has resistance to flow of current; can have a fixed or variable resistance.
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Semi-conductor
An electrical conductor where resistance decreases with increasing temperature and the presence of impurities;
the metalloids are semi-conductors. Note: metals, which are good conductors, are the opposite: resistance
increases as temperature increases
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Series circuit
A circuit in which there is only one path for electricity to travel.
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Short circuit
Fault in an electrical circuit that allows electric current to flow rapidly along a path of low resistance
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Thermistor
A temperature sensitive resistor. Heat onto the thermistor reduces its resistance
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Transformer
A device for changing an alternating voltage from one value to another which by the principle of
electromagnetic induction. An alternating current in the primary coil creates an alternating magnetic field,
which induces an alternating current in the secondary coil. The ratio of the voltage in the secondary to the
voltage in the primary is approximately equal to the ratio of the number of turns of wire in the secondary coil to
the number of turns in the primary coil.
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Transistor
Semi-conductor device used in a circuit as an amplifier, rectifier, detector or switch
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Transmitter
A device for transmitting a signal, typically by means of a radio wave
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Volt
Unit of electromotive force and potential difference (V).
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Voltmeter
Device to measure potential difference or voltage. Voltmeters are connected in parallel across a component,
e.g. a globe, whose voltage is being measured.
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electrons.