Why does an element in a circuit cause a "voltage drop"

In summary: Basically, the pressure is the same in all areas of the house until somebody turns on the water, and then the pressure decreases as more water is demanded.
  • #1
Mr Davis 97
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I have seen this topic in other threads before, but I have not found an answer that eliminates my confusion. I know that electric potential is defined so that only the position of a charge with respect to a field determines the quantity of the electric potential (voltage). This allows us to quantify, generally, how spatial orientation with respect to a field affects the specific potential energy of a specific charge with some amount of coulombs. This all being said, I don't understand why there is a "voltage drop" after charged particles enter an element (such as a resistor) in a circuit. If we say that a battery creates an electric field and thus well-defined electric potentials around the field, then how come there is a drop in electric potential after a particle enters a a resistor, if that charged particle is roughly the same distance from the battery which the electric field comes from? I've heard people say that there is a voltage drop because the charged particles lose energy in the resistor, but if voltage is electric potential and not electric potential energy, then how does the fact that they lose energy affect electric potential (voltage), which is defined as the amount of potential energy per coulomb? I think my confusion lies in the concept of voltage. Basically I don't know how voltage is supposed to drop when there is a definite, constant amount of voltage for the battery.
 
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  • #2
Suppose you have three resistors of equal value hooked in series with each other and with the battery. Would you expect the voltage across the middle resistor to be identical to the voltage of the battery? This would imply that the other two resistors are acting not like resistors but like wires. Ohm would be upset.
 
  • #3
Mr Davis 97 said:
If we say that a battery creates an electric field and thus well-defined electric potentials around the field, then how come there is a drop in electric potential after a particle enters a a resistor, if that charged particle is roughly the same distance from the battery which the electric field comes from?

My understanding, with some not-very-accurate terminology:

Remember that the charges all interact with each other. Charges moving through the resistor require more energy to move than charges in the conductor. You could say that the charges 'pile up' on one side of the resistor until the current flow through the conductor and the resistor are equal, and that the current is mostly limited by how many charges per second can pass through the resistor.

So the distance from the terminals doesn't matter since the charges just move around in response to each other's electric fields as well as the battery's.
 
  • #4
Mr Davis 97 said:
Basically I don't know how voltage is supposed to drop when there is a definite, constant amount of voltage for the battery.

You have constant water pressure delivered to you house from the regulator provided by the water company. The pressure is all the same, throughout your house--34 PSI, until someone turns on the water.

You're taking a shower, and someone turns on the dishwater. The water flow drops because the pressure at the nozzle decreases. (It is an unstated universal law, that the water always gets colder, but that's another story.)

This is because there there is a restistance, from the sides of the pipes, to impede the water from flowing. The more water that is in demand, the lower the flow rate, and the less pressure.

Were you asking about water pressure, right?
 

Related to Why does an element in a circuit cause a "voltage drop"

1. Why does an element in a circuit cause a "voltage drop"?

When current flows through a circuit, it encounters resistance from the various elements in the circuit such as wires, resistors, and other components. This resistance causes a decrease in the electrical potential energy of the current, resulting in a decrease in voltage. This decrease in voltage is known as a voltage drop.

2. How does the type of element affect the voltage drop in a circuit?

The amount of voltage drop in a circuit depends on the type of element and its resistance. Elements with higher resistance will cause a larger voltage drop, while elements with lower resistance will cause a smaller voltage drop. This is why resistors are often used in circuits to control and regulate the voltage.

3. Can a voltage drop be eliminated in a circuit?

No, a voltage drop cannot be eliminated entirely in a circuit. It is a natural occurrence due to the resistance of the elements in the circuit. However, it can be minimized by using elements with lower resistance or by using multiple elements in parallel to spread out the current and decrease the overall resistance.

4. How does the length of a wire affect the voltage drop?

The longer the wire, the higher the resistance and therefore the more significant the voltage drop. This is because the longer the wire, the more atoms the current must pass through, resulting in more collisions and a greater decrease in voltage. This is why it is important to use appropriately sized wires in circuits to minimize voltage drop.

5. Is a voltage drop always a bad thing in a circuit?

No, a small amount of voltage drop is acceptable and sometimes necessary in a circuit. For example, voltage drops are used to regulate and control the flow of current in a circuit. However, excessive voltage drops can lead to inefficiency and malfunctions in the circuit, so it is important to carefully design and manage voltage drops in a circuit.

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