Transcript of Conduction and Current Polarization vs. Conduction Batteries, Current, Resistance Ohm’s Law and...
- Slide 1
- Conduction and Current Polarization vs. Conduction Batteries,
Current, Resistance Ohms Law and Examples Resistivity and Examples
Power and Examples
- Slide 2
- Materials can do 2 things: Store charge Initial alignment of
charge with applied voltage Charge proportional to voltage
Temporary short-range alignment Conduct charge Continuous flow of
charge with applied voltage Current proportional to voltage
Continuous long-range movement Electrical Properties of
Materials
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- Charge Storage vs Conduction Storage Q = CV Charge in Coulombs
Energy stored in Joules Conduction V= IR (I=GV G=1/R) Charge flow
in Coulombs/second (amps) Power created or expended in Watts
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- Batteries Battery Electrochemical Source of voltage Positive
and negative 1.5 volt, 3 volt, 9 volt, 12 volt Circuit symbol
- Slide 5
- Current Coulombs/second = amps I = Q / t Example 18-1 Requires
complete circuit Circuit diagram Positive vs. negative flow
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- Resistance Resist flow of current (regulate) Atomic scale
collisions dissipate energy Energy appears in other forms (heat,
light) Applications Characterize appliance behavior Heater
(collisions cause heat) Regulate current/voltage on circuit board
Resistors and color code
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- Resistance and Ohms Law Storage vs. Conduction Q = CV (storage)
I = GV (conduction) Current proportional to voltage Proportionality
is conductance Use inverse relation V = IR Resistance Units
volts/amps = ohms Ohms law If V proportional to I, ohmic Otherwise
non-ohmic Example 18-3
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- Ohms Law Examples
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- Slide 10
- Resistivity vs. Resistance Property of material vs. property of
device Similar to dielectric constant vs. capacitance Becomes
resistance vs. resistivity We use reciprocals, resistance and
resistivity published for materials, like K. High poor conductor,
good conductor (similar to K for storage) StorageConduction
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- Resistivity of materials
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- Resistivity Example
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- Resistivity examples
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- Resistivity example
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- Power V 0 +
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- Power example
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- Power examples Problems 31, 32, 33, 38,
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- Power transmission
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- Power transmission 12,000 V
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- Power transmission 50,000 V
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- Power transmission 2,000 V