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20 Cards in this Set
- Front
- Back
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-current flows in one directions.
-power source has a definite polarity |
direct current
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-current that is continually changing in amplitude and periodically reversing direction (+ and -)
-amplitude= max amount of voltage |
alternating current
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-divided into 360 degrees (one cycle)
-max positive peak 90 degrees -max negative peak 270 degrees |
sine wave
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-instantaneous rise and fall
-symmetrical alternations |
square wave
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-instantaneous rise and fall
-non-symmetrical alternations |
rectandgular wave
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-linear rise time and sharp fall time
-non-symmetrical |
sawtooth wave
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the maximum value of one alternation (Epk)
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peak voltage
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voltage from the psoitvie peak to the negative peak
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peak to peak voltage
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AC voltages that produces some amt. of heat as a given DC voltage
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RMS (effective)
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one complete cycle equals 360 degrees consosting of 180 degrees positive and 180 negative alternation
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cycle
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the time it takes for one complete cycle to occur
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period-time-duration
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number of cycles in 1 second
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frequency
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symbol= f
unit of measure= Hertz symbol for unit of measure=Hz |
frequency
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-the distance between begining and end of one AC cycle
-unit of measure= meters -symbol for unit of measure= m |
wavelength
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two sine waves of the same frequency pass through zero and reach their postive peaks at the same time (90 degrees phase shift)
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in-phase
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two sine waves of the same frequency that do not pass through zero and the positive peak at the same time
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out-of-phase
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15 Hz to 20KHz (power frequencies (0Hz to 3KHz)
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audio frequencies
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20KHz to 300GHz (microwaves 1GHz to 300GHz)
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radio frequencies
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exentds to 10 to the 17th power
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optic
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extends to 10 to the 23rd power
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x-ray
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