Can I use a ordinary 1K ohm potentiometer to convert 12V to 5V?

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Discussion Overview

The discussion centers on the feasibility of using a 1K ohm potentiometer to convert 12V to 5V for powering an Arduino microcontroller. Participants explore the implications of using the potentiometer based on its specifications and suggest alternative solutions.

Discussion Character

  • Technical explanation, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant questions the suitability of the 1K ohm potentiometer for converting 12V to 5V, citing the maximum power rating and the power that would be applied as a concern.
  • Another participant suggests using a voltage regulator, specifically the 7805, as a more reliable solution than a potentiometer for providing a stable 5V output.
  • A third participant recommends the LM2931 voltage regulator, especially for automotive applications, highlighting its protective features against reverse polarity and overvoltage.
  • One participant strongly advises against using a potentiometer or resistor for voltage dropping in microcontroller applications, emphasizing reliability issues.

Areas of Agreement / Disagreement

Participants generally agree that using a potentiometer for this purpose is not advisable, with multiple competing views on the best alternative solutions, particularly regarding the choice of voltage regulators.

Contextual Notes

There are unresolved concerns regarding the power ratings and operational limits of the potentiometer, as well as the specific requirements of the Arduino microcontroller in terms of voltage and current.

Who May Find This Useful

Individuals interested in electronics, particularly those working with microcontrollers and voltage regulation, may find this discussion relevant.

marellasunny
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I have a 1K ohm potentiometer.(datasheet is attached below). My aim is to convert 12V to 5V,which I would then apply to power the Arduino microcontroller. I'm not quite sure if I CAN use the potentiometer I have ie T93 YA 1K 1035 to do this conversion.
The datasheet says that the maximum voltage applicable for 1K ohm is 22.5V. But,the MAX.power given is 0.5W. This doesn't make concurrence since my input voltage is at 12V and 0.6 A,which means the power applied would be 7.6W.So,does that imply this potentiometer could not be used for the purpose of 12V to 5V conversion?

How do I go about calculation?
I'm new to electronics stuff.
 

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Since the Arduino consumes a varying current but requires a fixed voltage you should use a voltage regulator. The 5 volt regulator part number you should look for is 7805, they are a commodity available everywhere. That will solve your problem better than any potentiometer you might use. If you use a potentiometer, at some time you will certainly exceed the specified maximum input voltage to the Arduino which will almost certainly destroy it.
 
Baluncore is exactly right, you need something automatic. 12 volts - is this for use in an automobile?

If so you might consider LM2931 regulator. It comes in 3 terminal like 7805 but is intended for automotive application so includes two nice features:
1. It's reverse polarity protected to protect your arduino against reversed battery leads when somebody makes a mistake giving you a jump-start
2. It has overvoltage protection to around 60 volts which protects against alternator surge caused by loose battery cables.

http://www.ece.ucsb.edu/Faculty/rodwell/Classes/ece218b/lab_projects/LM2931.pdf
 
Using a pot, or a resistor to drop voltage for a uP will never never never work reliably. Don't even think about it.
 

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