Measure potentiometer value using a constante current source

[metRo_]

Hi,
I need to measure a potentiometer value from a joystick. The usual way to do this is to use it as a voltage divider.

But I remember from university that I use a constant current source to measure the potentiometer value but I couldn't remember the advantages of that application beyond  this way if the power source varies I still get the same value.

Could you explain me if that application will give me best results? per example about noise?

PS: I'm thinking to use a lm334

Thanks

[AlphZeta]

but I couldn't remember the advantages of that application beyond  this way if the power source varies I still get the same value.

Hmm... the only thing I could think of is if you are measuring a resistance that changes so that by using a constant current (instead of constant voltage) you can avoid burning up the resistor should the resistance value be too small.

Other than that, the simplest way is to just have the potentiometer tied to ground and a regulated Vcc and measure the wiper voltage via ADC.

[kxenos]

If you want to read the ohmic value of an unknown resistor, it's easier if you have a constant current. The equation is R=V/I. If your I is constant then you only need to measure voltage to get the resistance. If you have a constant voltage then you measure the current. If you don't have neither constant voltage nor current you measure both.