circuit electricity may 30, 2012 chapter 22. terms current: flow of charge symbolized by “ i ”...
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![Page 1: Circuit Electricity May 30, 2012 Chapter 22. Terms Current: Flow of charge Symbolized by “ I ” Units = Coulombs/second = Amperes (A) Circuit:](https://reader036.vdocuments.us/reader036/viewer/2022082613/5697c0301a28abf838cdab8f/html5/thumbnails/1.jpg)
Circuit Electricity
May 30, 2012 Chapter 22
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Terms Current: Flow of charge
Symbolized by “I” Units = Coulombs/second = Amperes (A)
Circuit: a closed loop that current flows through
Resistance: Opposition to current Units = Ohms (Ω)
LED: Light Emitting Diode Used to test for presence of current.
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More Terms Volts: the force that pushes current
through a circuit Power: the energy delivered to the
circuit per second Power = (current)(voltage) P = (I)(V) Units = Watts
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Examples #1 & #2A car battery causes a current of 2.0 amps through a light while 12 V is across the battery. What is the power used by the lamp? P = (2.0)(12) P = 24 W
What is the current through a 75W lightbulb connected to a 120 V outlet? 75 = (I)(120) I = .625 A
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How does a light bulb light? As the current flows through the
filament, it encounters resistance Resistance: a material’s opposition to
current flow Ohm’s Law:
R = (V/I)As resistance increases, current decreasesAs voltage increases, current increases
The collisions between the current and material results in energy loss (heat and light)
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Examples #3 & #4 A car headlight has a resistance of 30Ω and is
hooked to a 12V battery. What is the current through the bulb? 30 = (12/I) I = (12/30) = .40 A
A lamp draws a current of .50A when connected to a 120-V outlet. What is the resistance of the lamp? R = (120/.50) R = 240 Ω
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Homework Ch 22 p 527-529 # 22,23,25,27,30,33,42,45