Conceptual Question about Voltage Drops

In summary, the conversation discusses the concept of current in a circuit and how it is determined before encountering any resistors. The speaker compares current to a bicycle chain and explains that it is influenced by the electric field created by the power supply and affected by the components in the circuit. They also mention the surface charge feedback theory and the initial transient in circuits.
  • #1
Jason Williams
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So I have one last roadblock to understanding how circuits fully work and it has to do with currents (in series). To my current understanding, if we were to have a simple DC circuit with one battery at 10V and one resistor at 10 ohms, the current at all points in the wire is 1 A. Now, if we were to connect another resistor of 10 ohms, the current would be then be .5 A.

I am essentially trying to figure out how is the current determined in the wire before it encounters any resistors. What I don't understand here is how is it possible for the electrons to know what speed to travel with when it doesn't know the resistances that are ahead of it? Shouldn't as much charge as possible be trying to escape the terminal of the battery regardless of the resistors ahead?

If the way I'm explaining it doesn't make any sense, I will gladly offer up a different explanation.

Thanks!
 
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  • #2
I always find it helpful to think of current as being like a bicycle chain. It doesn't make any sense to try to think of one link in the chain moving by itself. Either all links move at the same time or no links move.
 
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  • #3
Jason Williams said:
So I have one last roadblock to understanding how circuits fully work and it has to do with currents (in series). To my current understanding, if we were to have a simple DC circuit with one battery at 10V and one resistor at 10 ohms, the current at all points in the wire is 1 A. Now, if we were to connect another resistor of 10 ohms, the current would be then be .5 A.

I am essentially trying to figure out how is the current determined in the wire before it encounters any resistors. What I don't understand here is how is it possible for the electrons to know what speed to travel with when it doesn't know the resistances that are ahead of it? Shouldn't as much charge as possible be trying to escape the terminal of the battery regardless of the resistors ahead?

If the way I'm explaining it doesn't make any sense, I will gladly offer up a different explanation.

Thanks!
Watch "surface charges and circuits" on youtube.. Answer to your doubt lies in the surface charge feedback theory...You need to understand the very initial transient (which lasts for a few picoseconds) which is hardly discussed in the circuits course..
 
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  • #4
The electrons move inder the influence of the electric field which propagates
through the whole of the circuit. The field is setup by the power supply and
its propagation is influenced by the components in the circuit. I tend to think
of the situation like the ocean (electrons) and islands (the components), except
that the current goes through the islands under the influence of the pressure
difference (as evident by the waves present there) created on the shores of the islands.
 

FAQ: Conceptual Question about Voltage Drops

1. What is a voltage drop?

A voltage drop is the decrease in voltage that occurs when an electrical current flows through a circuit. It is measured in volts (V) and is caused by the resistance in the circuit components.

2. How do you calculate voltage drops?

Voltage drops can be calculated using Ohm's Law, which states that the voltage drop (V) is equal to the current (I) multiplied by the resistance (R) in the circuit. This can be represented by the equation V=IR.

3. Why do voltage drops occur?

Voltage drops occur due to the resistance in the circuit components, such as wires, resistors, and other electrical components. This resistance causes the electrical energy to be converted into heat, which results in a decrease in voltage.

4. Can voltage drops be prevented?

While some voltage drops are unavoidable, they can be minimized by using thicker wires and higher quality components with lower resistance. Proper circuit design and regular maintenance can also help prevent excessive voltage drops.

5. What are the consequences of voltage drops?

Excessive voltage drops can lead to a decrease in the performance of electrical devices, as they may not receive enough voltage to operate properly. This can also result in overheating and potentially damaging the circuit components.

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