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center of the nucleus with an electrical charge
neutron
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protons
in the nucleus with a positive charge
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electrons
circle the nucleus with a negative charge
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most elements have a ___ charge
neutral
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in ____, electrons can be easily dislodged from their orbits and attract to other atoms
metals
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electricity
flow of electrons
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direct current
an electrical circuit through which the flow of electrons moves only in one direction, electrons have to loop to connect bulb and battery
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most video equipment
direct current
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interrupts the flow of electrons
switches
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alternating current
flow of electrons change direction constantly, negative to positive to negative
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efficient for transmission through wires over long distances, household electricity
alternating current
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the pressure of the electricity
voltage, measured in volts
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voltage: ____ is constant
speed is constant, pressure is not
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the volume of electrons, number of electrons passing a certain point in a given time
current, measured in amps
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determined by voltage and current, measurement of work accomplished
power, measure in watts.
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property of a material to resist the flow of electrons through when voltage is applied
resistance, measured in ohms
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electricity in television
frequency, AC frequency, Impedance
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action that repeats itself, an electrical circuit that puts out repeated and equal bursts of energy
frequency, 100 bursts a second has a frequency of 100 Hz
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AC Frequency
if the electricity in your home is 120 V AC, the electricity will go from 0V to 120V, back down to O then to -120V then up to 0...one cycle. household has 60 times a second=60Hz=120 V 60 Hz AC
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impedance
the combination of resistance, capacitance, and inductance. helps to tell the crew if 2 or more circuits will interact well.
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if amp has an impedance of 8 ohms then you need to hook up speakers with ___resistance
8 ohm
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fields (induction)
any electrical circuit that has a changing flow of electrons will create an electromagnetic field around itself
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a high-tension power line running cross country has an extremely ___ electromagnetic field
strong
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signal-to-noise ratio
the relationship between the strength of the signal and the amount of noise the circuitry creates, dB, logarithmic ratio
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average ear hears sounds between
20 Hz and 15,000 Hz
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early technology allowed recordings of up to _____ until late 1940s
5,000 Hz
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HDTV standard accepted is
5.1 surround sound stereo standard
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five main speakers used in 5.1 surround sound stereo
left front, center front, right front, right surround and left surround and subwoofer
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subwoofer
the .1 for very low sounds that can be placed anywhere in surround sound
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consumer video is ____ impedance
high, 10,000 ohms
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consumer audio is ______
unbalanced, uses 2 wires to carry message and does not resist induced noise
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balanced audio systems
uses 3 wires to carry message and resist induced noise
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3 wires of balanced audio system
one is ground, two carry the same signal ("in phase") but noise is likely to hit the 2 wires at different times ("out of phase"). equipment getting the signal will let things in phase pass but filter out "out of phase" noise. both lines of the system must be balanced.
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mics create own ____ and have very ___ signals
electricity, weak. 40 to 60 dB lower than line.
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to record natural sound, first step is
a microphone
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microphones
transducer that changes sound into electrical energy. all have highly flexible diaphragm that vibrate with sound movements in air to create a very small electrical voltage that passes on to next piece of equipment in system
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"digital" mics
will have an A to D converter attached to diaphragm circuitry to create the digital signal-requires electrical circuitry and power. large and bulky.
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mixer
brings several sound sources together, measure their strength and hear them. wont hear them unless they go through mixer
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difference between analog and digital mixers
analog only deals with analog sound. digital deals with both and have built in A to D converters and are more expensive
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loudspeakers
analog transducer that converts electrical energy into sound energy
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how loudspeakers work
has small piston wrapped in coil of fine wire mounted inside a magnetic field, piston is attached to a flexible cone, the coil creates a changing electromagnetic field that interacts with surrounding magnetic field causing piston to move back and forth. makes sound.
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for digital video, we use ____ sampling rates and ___ processing levels
high sampling rates (in megahertz), low processing levels (8- or 10- bit processing)
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for digital audio, we use ___ sampling rates and very ___ processing
low sampling rates (48,000 Hz on digital videotape) and very high processing (16 bit)
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audio compression
done by dividing the frequency range into different bonds of frequencies and compressing them separately
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recording process
sound will enter the recorder from the mic and will enter an A to D converter where it is put down on recording medium as series of 0s and 1s. when played back it goes through a D to A converter
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uncompressed vs compressed
uncompressed is better than compressed
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digital audiotape recorder
DAT: uses a rotating head wheel that moves opposite of tape, somewhat delicate and easy to break, downloading the info to a computer takes real time
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Digital Audio Workstations
DAW: high budget productions, send audio in the form of a computer file to a professional sound company for editing, processing, adding of sound effects
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