The circuit of a voltage divider may be drawn with the two resistors vertical, not horizontal. If there are two resistors in series across a voltage source, then the circuit is a voltage divider.
But that means using the voltage divider equation, and the difference in voltage between keys can get very small. Dropping the voltage divider and measuring the current through a current mirror ...
The input voltage in this circuit is equal to the voltage across the thermistor. Use the voltage divider equation to calculate the voltage (\(V2\)) across the thermistor. \({V_2} = {V_s} ...