Voltage and current explained

June 30, 2021
 by Paul McGowan

3 comments on “Voltage and current explained”

  1. I’ve always found that the ‘water running through a garden hose’ analogy works well for the layperson.
    Water pressure is the EMF (voltage); the actual water is the current (amps) & the flow of the water is the wattage (being a combination of water pressure times water)…oh, & the diameter of the hose is the resistance (ohms), ie. as the diameter of the hose increases (resistance decreases) more water (current) must present.

    Another example that I have heard of is a church on fire on a Sunday morning.
    The size of the fire is the EMF; the number of people in the church is the current & the speed & force with which the people run screaming out of said church is the wattage.
    🙂

  2. The water analogy is quite useful. There’s an interesting project here: https://www.kickstarter.com/projects/upperstory/spintronics-build-mechanical-circuits. The creator of Spintronics considered building a system based on water, but decided it was too messy. Instead, he uses torque as the analogue for voltage, and the speed of the belt as the analogue for current. The friction in the pulleys is resistance. I don’t have Spintronics, but I do have the previous product Turing Tumble, and it’s pretty interesting and well constructed.

  3. This is how I would explain it:
    The Voltage is representing the level of “static” energy of the power supply, amplifier etc. Using the water analogy, it is the energy that for example a 100 liter container filled with water placed 20 meters above ground represents. One would have the feeling, if this would have fallen down how much damage could have caused in the ground. But until one does not open the faucet, this energy is just there, has no any effect.
    When one opens the faucet, the static is transformed into moving energy, and this is what you are able to feel it (look at a tzunami, how much moving energy can have)
    In the electrical circuit this flow is done by the free electrons. When you’re closing the circuit (connect a speaker) the electrons starts to move, so the Amper is the moving energy. In other words the statical (Volts) energy is converted into moving (Amper) energy. The higher is the Voltage (statical potential to be converted to moving energy) the higher the Amper is. The resistor is the factor that controls of how much of the statical energy can be converted to moving energy.

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