FHSST Physics/Electricity/Ohm's Law Analogy

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The Free High School Science Texts: A Textbook for High School Students Studying Physics
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Electricity
Flow of Charge - Circuits - Voltage and Current - Resistance - Voltage and Current in a Practical Circuit - How Voltage, Current, and Resistance Relate

- Ohm's Law Analogy - Power in Electric Circuits - Calculating Electric Power - Resistors - Nonlinear Conduction - Circuit Wiring - Polarity of Voltage Drops - Series and Parallel - Simple Series Circuits - Simple Parallel Circuits - Power Calculations - Using Ohm's Law - Conductor Size - Fuses - Important Equations and Quantities

An analogy for Ohm's Law[edit]

Ohm's Law also make intuitive sense if you apply it to the water-and-pipe analogy. If we have a water pump that exerts pressure (voltage) to push water around a "circuit" (current) through a restriction (resistance), we can model how the three variables interrelate. If the resistance to water flow stays the same and the pump pressure increases, the flow rate must also increase.

If the pressure stays the same and the resistance increases (making it more difficult for the water to flow), then the flow rate must decrease.

If the flow rate were to stay the same while the resistance to flow decreased, the required pressure from the pump would necessarily decrease.

As odd as it may seem, the actual mathematical relationship between pressure, flow, and resistance is actually more complex for fluids like water than it is for electrons. If you pursue further studies in physics, you will discover this for yourself. Thankfully for the electronics student, the mathematics of Ohm's Law is very straightforward and simple.