Potentiometer

Thread Starter

tami

Joined Nov 27, 2012
1
Hi everyone,
I am working with potentiometer.I want to connect it to FEZ Mini's analog Input pin(which is 3.3V max) to convert analog into digital. That analog input pin won't take voltage more then 3.3volts or it will blow the microcontroller up, so I want my potentiometer to connect to 3.3V instead of 5volts, which I am not sure about...? So my question is - Can I connect my 10k linear potentiometer to 3.3V instead of 5V to make it work with Fez mini's analgInput pin?
 

tshuck

Joined Oct 18, 2012
3,534
Hi everyone,
I am working with potentiometer.I want to connect it to FEZ Mini's analog Input pin(which is 3.3V max) to convert analog into digital. That analog input pin won't take voltage more then 3.3volts or it will blow the microcontroller up, so I want my potentiometer to connect to 3.3V instead of 5volts, which I am not sure about...? So my question is - Can I connect my 10k linear potentiometer to 3.3V instead of 5V to make it work with Fez mini's analgInput pin?
yup, no problem...
 

wayneh

Joined Sep 9, 2010
17,496
Hard to follow without a drawing, but you'll want an external fixed resistor also, for insurance against the pot being turned all the way to one end, to zero ohms. You think it won't happen, but it will.

I think you just need a voltage divider, so that a 5v input is scaled down to 3.3V. You may not even need a pot.
 

tshuck

Joined Oct 18, 2012
3,534
As long as it is hooked up as it is here there should be no problem. The center tap will be what is connected to your ADC input and the two fixed points to your supplies...

Hard to follow without a drawing, but you'll want an external fixed resistor also, for insurance against the pot being turned all the way to one end, to zero ohms.
If it's connected properly, the supply will always see a 10kΩ resistance, regardless of where the wiper is...
 

wayneh

Joined Sep 9, 2010
17,496
Huh, guess I totally missed the point of the question. :confused: Wouldn't be the first time.

I thought he wanted to use the pot to protect the input against ever seeing 5v.
 

tshuck

Joined Oct 18, 2012
3,534
Huh, guess I totally missed the point of the question. :confused: Wouldn't be the first time.

I thought he wanted to use the pot to protect the input against ever seeing 5v.
Ah, yes, then that would be a valid point!

To be honest, I had to go back and re-read it to be sure ;)
 
Top