I have a variable resistance, 1K to 1M. As it varies due to external factors, I want to be able to pick a X value in between 1K and 1M so that once it reaches X even if the resistance increases the resistance is capped to X.
For example. I want to limit the upper bound to 1.7K. As the variable resistance crosses 1.7K I want the resistance the circuit sees to stay at 1.7 instead of keep increasing.
What kind of circuit can I resort to in order to achieve that behavior?
- When variable resistance value is below upper bound X the value seen should match the value of the variable resistance.
- The resistance is probed keeping voltage constant