(need some easy help) Changing a potentiometer to a switch

This is a suppose a simple question, but im still new to electronics. A device I have has a potentiometer. Id like to change this to a simle on/off swich.

There are three wires coming off of the potentiometer. Positive, Negative and Signal. How do i wire these to a switch to give either all or nothing perfomance (on/off)?

Thanks!

You need to add an active component. Google comparator. See how fixing one input to a known voltage and the other input to your pot wiper can result in just the behavior you have described.