Calculating Resistor Size for 3V Battery: A Guide

In summary, the conversation discusses using a 5.1V Zener diode in a regulator for charging a 3V battery, with one participant advising against it due to safety concerns and recommending a 3-terminal linear regulator instead. The other participant suggests using a 35Ω, 50W resistor for this approach, but also recommends checking out batteryuniversity.com for more information on battery charging.
  • #1
John1397
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18
Found this online I added 3 volt battery how do you figure out what size resistor to use?
 

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  • #2
You cannot use a 5.1V Zener diode in a regulator for charging a 3V battery...

And Zener regulators are pretty sloppy anyway -- in general it's a lot better to just use a 3-terminal linear regulator. And battery charging can be a fairly complicated matter, depending on which battery chemistry you are working with...

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  • #3
@John1397, As berkeman stated...

berkeman said:
You cannot use a 5.1V Zener diode in a regulator for SAFELY charging a 3V battery...
Since you didn't give many details, here is the scenario:

If you really insist on this approach, do it out doors, nothing around that you want to keep (like people, animals, or houses), and don't mind destroying a battery, then a 35Ω, 50Watt resistor would be about right.

Oh, and stay up-wind of it.

I really recommend that you take heed of the approach by @berkeman though.

That said, here is a sight with a great amount of information about batteries and how to charge and use them: https://batteryuniversity.com

Cheers,
Tom
 
  • #4
Tom.G said:
If you really insist on this approach, do it out doors, nothing around that you want to keep (like people, animals, or houses), and don't mind destroying a battery
LOL 😉
 
  • #5
berkeman said:
... battery charging can be a fairly complicated matter, depending on which battery chemistry you are working with...
Indeed. :approve:

For the OP, check out https://batteryuniversity.com/index.php/learn/.
 
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1. How do I calculate the resistor size for a 3V battery?

To calculate the resistor size for a 3V battery, you will need to know the voltage of the battery and the desired current. Using Ohm's law (V = IR), you can rearrange the equation to solve for resistance (R = V/I). Simply plug in the values of 3V for V and the desired current in amperes for I, and you will get the resistance in ohms.

2. What is the purpose of using a resistor with a 3V battery?

A resistor is used with a 3V battery to limit the amount of current flowing through a circuit. This is important because if too much current flows, it can damage the components in the circuit. The resistor acts as a "speed bump" for the current, reducing it to a safe level.

3. Can I use any resistor size with a 3V battery?

No, you cannot use any resistor size with a 3V battery. The resistance value of the resistor should be carefully calculated to ensure that the current is limited to a safe level. Using a resistor with too low of a resistance can cause the battery to overheat and potentially explode.

4. How do I know which resistor size to choose for my circuit?

The resistor size you choose will depend on the desired current for your circuit and the voltage of the battery. You can use Ohm's law (V = IR) to calculate the resistance needed, or you can use online calculators or reference tables to find the appropriate resistor size for your circuit.

5. Are there any other factors to consider when choosing a resistor size for a 3V battery?

Yes, there are a few other factors to consider when choosing a resistor size for a 3V battery. These include the power rating of the resistor (to ensure it can handle the amount of current flowing through it), the tolerance (to ensure accuracy), and the physical size and shape of the resistor (to fit in your circuit design).

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