Question

 Assume that you are supplied with a translational potentiometer sensor with the following properties;

* 100 V DC Power Supply,

* 1 resistive wire: 40 mm long with 1mm² cross-section area. ( resistivity=0,00025 Ohm m)

 It is also given to you that;

 -In the initial state (where no force is applied to the system) of the potentiometer, movable arm of the output voltage positioner covers 90% (length) of the resistive wire.

- When 10N of force is applied to the system you observe 6mm displacement (in (-) y direction) of the movable arm of the output voltage positioner

 

Calculate what is the output voltage change caused by the 10N of force? 

Answer 1

Determine the maximum resistance:

$$R=\rho L/A=10\Omega.$$

Determine the current:

$$I=V/R=10\text A.$$

The voltage across the arm without load:

$$V_1=IR_1=(1-90/100)IR=10\text V.$$

The voltage across the arm with load:

$$V_2=IR_2=IR·\frac{0.1·40+6}{40}=25\text{V}.$$

The output voltage change:

$$\Delta V=V_2-V_1=15\text{ V}.$$