# Limit variable resistance upper bound?

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?

Requirements:

1. When variable resistance value is below upper bound X the value seen should match the value of the variable resistance.
2. The resistance is probed keeping voltage constant
• I thought about that, but, wouldn't that make it so when the variable resistance is below 1.7K, let say 1.2K, the circuit would not see 1.2K but 703.45 ? I am looking for a way to limit the upper bound while keeping the behavior below the upper bound the same.... – stoic Feb 26 at 17:40
• Makes sense. So I am looking for a constant voltage scenario as far as the probing goes... – stoic Feb 26 at 17:54
• Use two pots in parallel. I'd put course pot in series with 1k resistor. Other becomes a fine. – StainlessSteelRat Feb 26 at 18:45