[Unlocked] Nervous System Sends Messages
- Identify what parts of the body would be considered series and what parts would be considered parallel.
The best example of how the body would be considered series and parallel is the central nervous system, which include the brain and the spinal cord. The nervous system sends messages back and forth from the brain (power source), through the spinal cord and to the nerves throughout the body. The brain sending signals down the spinal cord would be considered series. Signals are sent through the peripheral nerves and to the muscles, glands and organs throughout the body would be considered parallel.
- Discuss how the series and parallel systems function together as a series-parallel circuit in your analogy.
The brain, which would be the power supply, sending signals down the spinal cord would be the series system. The body cannot function without the brain sending signals through the spinal cord and to the rest of the body, which makes it analogous to a series circuit. Signals sent from the spinal cord to the peripheral nerves would be the parallel system because one side can function independently from the other.
- Explain how electricity can travel through the body using a series-parallel electrical model. How does this relate to touch, step, and step-touch potential?
Let’s say that there is a broken overhead power line and it makes contact with the ground while it is still energized. The touching point of the power line and the ground has now produced a huge potential value, and everything within a 10 meter radius of the contact could also be energized. Electricity spreads like ripples or rings over the surface of the ground away from the point of contact. Each “ring” carries a different potential value. If you step in one ring while your other foot is in another, this different potential values on both legs will cause the electrons to travel through your body from high potential to low potential which results in an electric shock (SCGA, 2019). This is an example of step potential.
If you touch a vehicle, or any other object, that is in contact with the broken power line, this will cause a potential difference between hand (high potential) and leg (low potential). The electricity will travel through your body to get to the ground (SCGA, 2019). This is an example of touch potential.
- Finally, Discuss the loading effect of a voltmeter on a circuit. How does the voltmeter’s internal resistance affect the loading effect?
The loading effect of a voltmeter is the difference between actual voltage that exists in the circuit without connecting the voltmeter and the voltage that appears after connecting a voltmeter (EEE, 2019). The voltmeter has an internal resistance and therefore draws some current to measure the voltage when placed across a resistor. This is because more current will always flow through the path of least resistance. Therefore, the voltage drop across the resistor will be less than the actual voltage drop due to the voltmeter. This also results in the voltmeter showing a value lower than the true value of the reading (Electrical Deck, 2021).
SCGA. (2019). Understanding Step and Touch Potential. https://www.youtube.com/watch?v=LdhP-vGaxtc
Electrical Deck. (2021, April 25). Sensitivity of Voltmeter and Loading Effect of Voltmeter. Electrical Deck. https://www.electricaldeck.com/2021/04/sensitivity-of-voltmeter-and-loading-effect-of-voltmeter.html#:~:text=For%20high%20resistance%20circuits%2C%20the,loading%20effect%20of%20the%20voltmeter Links to an external site..
Engineering, E. A. E. (2019, July 28). Loading Effect of Voltmeter. Electrical and Electronics Engineering. https://electricalandelectronicsengineering.com/loading-effect-of-voltmeter/