# Battery with internal resistor

• jimmyting
In summary, the conversation discusses the calculation of current in a circuit with a battery that has an internal resistance. The internal resistance is considered to be in series with the other resistor, allowing for the calculation of an equivalent resistor. However, it is important to note that the potential drop across the terminals includes the internal resistance of the battery. The conversation also mentions the use of Hyperphysics as a helpful resource for understanding this concept.

#### jimmyting

[SOLVED] Battery with internal resistor

## Homework Statement

What is the current in a 8.25 ohm resistor connected to a battery that has a .21 ohm internal resistance when the potential drop across the terminals of the battery is 6V?

## Homework Equations

$$R_{s}=R_{1}+R_{2}...$$

$$V=IR$$

## The Attempt at a Solution

So I believe that the internal resistor can just be considered being in series to the other resistor, allowing me to calculate the equivalent resistor. Then with that, using V=IR, I thought I was able to get the current flowing through the circuit. I got .70921 A
Can someone correct my train of thought?

jimmyting said:

## Homework Statement

What is the current in a 8.25 ohm resistor connected to a battery that has a .21 ohm internal resistance when the potential drop across the terminals of the battery is 6V?

## Homework Equations

$$R_{s}=R_{1}+R_{2}...$$

$$V=IR$$

## The Attempt at a Solution

So I believe that the internal resistor can just be considered being in series to the other resistor, allowing me to calculate the equivalent resistor. Then with that, using V=IR, I thought I was able to get the current flowing through the circuit. I got .70921 A
Can someone correct my train of thought?
Note that the potential drop across the terminals includes the internal resistance of the battery. The internal resistance of a battery may be depicted thus,

So the actual emf of the battery is the 6V plus the voltage drop across the internal resistance. Do you follow?

Image courtesy of Hyperphysics

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jimmyting said:
Yes I do thank you for your help.
No problem.
jimmyting said:
Hyperphysics is an excellent general physics reference, I'm glad that you chose to look there rather than Wikipedia

## 1. What is a battery with internal resistor?

A battery with an internal resistor is a type of battery that has a resistor built into it. This resistor is used to limit the amount of current flowing through the battery, thereby protecting it from damage and extending its lifespan.

## 2. How does a battery with internal resistor work?

The internal resistor in a battery works by restricting the flow of electrons through the battery. This helps to prevent the battery from overheating and becoming damaged. It also helps to regulate the voltage output of the battery, ensuring a more stable and consistent power supply.

## 3. What are the benefits of using a battery with internal resistor?

One of the main benefits of using a battery with internal resistor is that it helps to protect the battery from damage and extends its lifespan. Additionally, it helps to provide a more stable and consistent power supply, making it ideal for sensitive electronic devices.

## 4. Can a battery with internal resistor be replaced?

Yes, a battery with internal resistor can be replaced. However, it is important to note that the internal resistor is an integral part of the battery and replacing it may affect the performance and lifespan of the battery. It is recommended to consult with the manufacturer or a professional before replacing the battery's internal resistor.

## 5. What types of devices are suitable for using a battery with internal resistor?

Batteries with internal resistors are commonly used in electronic devices that require a stable and consistent power supply, such as laptops, smartphones, and other portable electronic devices. They are also commonly used in electronic circuits and equipment that require protection from overcurrent.