Potential difference across parallel circuits

In summary, the potential difference across individual components in a parallel circuit is the same due to the definition of potential difference and the fact that all wires in a circuit are assumed to be ideal. This means that if two components share the same terminals, the potential difference across them will be the same. This can be seen in the example of two resistors of different resistance connected in parallel, where the resistor with less resistance will have more current and therefore dissipate more power. The explanation for this phenomenon lies in the ratio of work done by the charges to the amount of charges, which is always the same in parallel branches. However, it should also be noted that real wires have finite resistance, which can affect the voltage measured across parallel components.
  • #36
belliott4488 said:
Wait a minute! That's what's wrong. :eek: Lower resistance -> more current -> MORE power dissipated!

This is something I used to get backwards, until I got my intuition fixed. A larger resistance does NOT present a larger load to a voltage source, despite what you'd think based on the wording. This is clear if you just think in extremes - an open circuit presents an infinite resistance but no load at all, whereas a short-circuit presents zero resistance and generally fries things (too high a load).


Ahh I do know that. The intuition is wrong. Haha
 
Physics news on Phys.org
  • #37
FrogPad said:
Imagine a water pump hooked up to two pipes, in a configuration as like the one below with my beautiful ASCII art.

---W------________======B=======
|--------|___A___//_______________\\
|--------|======__________________=====D===
|--------|_______\\_______________//
----------________======C=======


If the water pump is W, and B and C are equal pipes. What would be the water pressure through A? What about the pressure at B and C. How would the flow of water change through B and C? What would the flow through A be compared to D?

Hey Frogpad, some problems with understanding the water analogy (again).

Alright. So by Bernoulli's Principle, in order for pressure to decrease (potential in electric circuit), the speed of the water must increase.

If we input resistances such as water wheels in pipes B and C, when water flows past these water wheels, the kinetic energy decreases, and hence speed decreases and hence pressure increases?!

Why is this so? It's so strange.

Even if we accommodate by inputting pipes of smaller radius after the wheel, the speed will increase (mass flow rate remains the same). But it just seem illogical!
 
Back
Top