How would you calculate the input voltage with a pen deflection of 18mm and a sensitivity of 5 uV/mm?

To calculate the input voltage based on pen deflection and sensitivity, you multiply the deflection measurement by the sensitivity value. In this case, a pen deflection of 18 mm and a sensitivity of 5 µV/mm means that for every millimeter the pen deflects, the voltage changes by 5 microvolts.

So, by multiplying 18 mm by 5 µV/mm, you get a total input voltage of 90 µV. This operation is essential in systems where signal amplitude is proportional to the measurement, which is typical in many biomedical devices. Multiplication effectively scales the deflection to the corresponding voltage output as determined by the system's sensitivity.