30 lines
916 B
Markdown
30 lines
916 B
Markdown
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#notes
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#school
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#electricity
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Summary:
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- **Voltage** is the difference in charge between two points.
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- **Current** is the rate at which charge is flowing.
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- **Resistance** is a material’s tendency to resist the flow of charge (current).
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- Water = **Charge**(Coloumbs)
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- Pressure = **Voltage**(Volts)
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- Flow = **Current**(Amps)
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- Hose Width = **Resistance**(Ohms
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### Equations
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- V = Voltage in volts
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- I = Current in amps
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- R = Resistance in ohms
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Solving for Voltage:
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`V = I * R`
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Solving for Current:
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`I = V / R`
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Solving for Resistance:
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`R = V/I`
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### Applying Concepts
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If a resistor has a 20 mAh current rating, and it's being powered with a 9 volt battery.
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To find the appropriate resistor for the LED, you solve for resistance with `R = V/I`, where V=9 and R = a number less than 0.02, like `9/0.018 = 500`, so you would want a resistor with a voltage at or greator than about 500 Ohms.
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