Smiple circuit with just one resistor

In summary, the conversation discusses how increasing the voltage in a simple circuit with one resistor affects the flow of current. It is mentioned that increasing the voltage provides the charge with more energy, but some charge can still get through even with a low voltage. The reason for the increase in current with higher voltage is attributed to the charge circulating faster due to a higher potential difference. However, this reasoning is deemed incorrect. The conversation also addresses the misconception that a minimum energy is needed to pass through a resistor. Ultimately, it is concluded that increasing voltage does increase the energy per coulomb, but it is not the reason for the increase in current.
  • #1
adamg
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In a smiple circuit with just one resistor, consider the current that flows. If you increase the resistance, less current flows. If you increase the supply voltage, the current increases.
One book says that increasing voltage provides charge with the energy needed to get through the resistor, but even when the supply voltage is very low, some charge still gets through doesn't it, just not very much.
So increasing the voltage does increase the energy per coulomb, but this can't be the reason why more current flows can it, because the charge can get through even when it has a low energy?
The only think i could think of is that a higher voltage makes the charge circulate faster due to the higher potential difference, but that sounds a bit wrong.
Can anyone help me out please? Basically i just want to know how come increasing voltage increases the current? And how come when you increase the voltage, more energy is dissipated for a given resistance? Because it can't suddenly become harder for charge to get through a resistor when you inrease the supply voltage can it?
 
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  • #2
Think of a garden hose. Blow into it with your mouth. The pressure with which you blow is analogous to voltage. More pressure->more flow and also more energy dissipated.
One book says that increasing voltage provides charge with the energy needed to get through the resistor
This implies you need a minimum energy to get through the resistor. That's wrong. A resistor is not a threshold device. Either the book is wrong or you paraphrased it incorrectly.
So increasing the voltage does increase the energy per coulomb
That's absolutely right. It's the definition of voltage.
 
  • #3


Increasing the voltage in a simple circuit with just one resistor does indeed increase the amount of current flowing through the circuit. This is due to Ohm's Law, which states that the current through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance of the conductor. In other words, as the voltage increases, the current increases proportionally, and as the resistance increases, the current decreases proportionally.

You are correct in thinking that increasing the voltage provides the charge with more energy to get through the resistor. However, even when the supply voltage is very low, some charge will still be able to flow through the circuit. This is because the resistor still offers some resistance to the flow of current, no matter how low the voltage is.

The reason why increasing the voltage results in more energy being dissipated for a given resistance is because the voltage is the driving force behind the flow of current. When the voltage is increased, more energy is available to push the charge through the circuit, resulting in a higher current. This higher current means that more charge is flowing through the resistor per unit time, leading to more energy being dissipated.

To answer your question about why it can't suddenly become harder for charge to get through a resistor when you increase the supply voltage, the key thing to remember is that the resistance of a resistor is a constant value. It does not change with the supply voltage. So, while increasing the voltage may make it easier for charge to flow through the resistor, the resistance remains the same.

In conclusion, increasing the supply voltage in a simple circuit with just one resistor results in more current flowing through the circuit due to Ohm's Law. This increased current also leads to more energy being dissipated for a given resistance.
 

Related to Smiple circuit with just one resistor

1. What is a simple circuit with just one resistor?

A simple circuit with just one resistor is a basic electrical circuit that consists of a power source, a resistor, and a closed loop for the current to flow through. The resistor is a passive component that resists the flow of electricity and is used to control the amount of current in the circuit.

2. How does a simple circuit with just one resistor work?

In a simple circuit with just one resistor, the power source provides the voltage that pushes the electrons through the circuit. As the electrons flow through the resistor, they encounter resistance, which causes them to slow down and lose energy. This results in a decrease in current flow and a voltage drop across the resistor.

3. What is the purpose of a resistor in a simple circuit with just one resistor?

The purpose of a resistor in a simple circuit with just one resistor is to limit the amount of current in the circuit. This can be used to protect other components in the circuit from damage, to control the brightness of a light bulb, or to regulate the voltage in the circuit.

4. How do you calculate the current and voltage in a simple circuit with just one resistor?

To calculate the current in a simple circuit with just one resistor, you can use Ohm's Law (I = V/R), where I is the current in amps, V is the voltage in volts, and R is the resistance in ohms. To calculate the voltage drop across the resistor, you can use the formula V = IR, where V is the voltage in volts, I is the current in amps, and R is the resistance in ohms.

5. What happens if the resistor in a simple circuit with just one resistor is replaced with a lower resistance?

If the resistor in a simple circuit with just one resistor is replaced with a lower resistance, the current in the circuit will increase. This is because the lower resistance allows more electrons to flow through, resulting in a larger current. The voltage drop across the resistor will also decrease, as the electrons encounter less resistance and lose less energy.

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