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41 Cards in this Set
- Front
- Back
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The science of electric charges in motion.
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Electrodynamics
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The amount of the electric charge flowing per second.
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Electric current
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Moving particles that carry an electrical charge
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Current carriers
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A circuit in which the current has a complete path to follow.
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Closed electrical circuit
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A circuit that has a break in it at any point. Doesnt have a complete path.
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Open electrical circuit
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The direction of the current flow in a circuit. Direction from positive to negative.
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Polarity
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Electric energy expended per second. The product of current and voltage.
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Power
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Conditions where electric current may occur.
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In a vacuum
In a gas In an Ionic solution In a metallic conductor |
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Is a place from which air has been removed.
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Conditions where electric current may occur:
In a Vacuum |
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Two oppositely charged electrodes placed in gas will cause positive ions, usually present in the gas to drift toward the negative electrode (cathode) and the negative ions to drift toward the positive electrode (anode).
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Conditions where electric current may occur: In a Gas
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Upon being dissolved in water a salt separates into its component ions.
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Conditions where electric current may occur:
In an Ionic solution |
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An electric current in a solid conductor consists of a flow of electrons only.
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Conditions where electric current may occur:
In a metallic conductor |
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Essential parts of a simple electric circuit:
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Battery
Conductor Load or resistance |
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The source of power
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Essential parts of a simple electric circuit: Battery
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The path where current flows
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Essential parts of a simple electric circuit: Conductor
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The part supplied with power.
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Essential parts of a simple electric circuit:
Load or resistance |
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The current in a circuit supplied by a battery has a definite direction, or polarity.
Cathode (-) -> (external circuit) -> Anode (+) |
Direction of current in a circuit supplied by batteries.
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Factors of an electric circuit:
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Potential Difference (voltage = V) (Electromotive Force = EMF)
Current (A = ampere or amps) Resistance (Ohms = Ω) |
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Diagnostic radiographic equipment utilizes _______ units to regulate the number of electrons available to produce xray photons.
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milliamperage
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Defined as a difference in electrical potential energy between two points in an electric circuit.
=> It is the difference of potential that drives the electrons. |
Potential difference (Voltage) (EMF = Electromotive Force)
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The unit of measure for potential difference is the?
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Volt = Is defined as the potential difference which will maintain a current of one ampere in a circuit whose resistance in one ohm.
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The amount of electric charge flowing per second. ( The quantity or number of electrons flowing)
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Current
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The unit of measure for current is the?
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Ampere
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May be defined as one coulomb quantity of electric charge flowing per second (i.e. 6.3 x 1010 free electrons per second)
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Ampere = A
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Types of electric current:
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Direct current = DC
Alternating current = AC |
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Current flow in one direction
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Types of electric current:
DC |
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Current oscillates back and forth.
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Types of electric current:
AC |
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The property of the circuit or substance which opposes or hinders the flow of an electric current.
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Resistance
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Unit of measure for resistance?
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Ohm:Ω
One ohm is the resistance of a standard volume of mercury under standard conditions. |
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FOUR FACTORS THAT AFFECT THE RESISTANCE OF CONDUCTORS:
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Type of material
length Cross sectional area Temperature |
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Certain materials that readily allow the flow of electrons.
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Conductors
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Materials that offers high resistance.
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Insulators
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Materials that offers moderate resistance.
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Semi-conductors
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Resistance is directly proportional to the ____ of the conductor.
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Length
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As length doubles, the resistance will?
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Also double
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The resistance of a conductor is inversely proportional to the?
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Cross-sectional area:
As cross sectional diameter doubles the resistance will be halved. |
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Heat is a simply measurement of the amount of atomic and molecular energy. With metallic conductors, the resistance becomes greater as the _____ rises.
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Temperature
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States that the value of the current in a metallic circuit equals the potential difference divided by the resistance.
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OHM's Law:
I=V/R |
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What is the formula for Power?
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P = I x V
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Unit of Power
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Watts
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1 horsepower is equal to __ watts?
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746 watts
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