The throttle lever was realized using a potentiometer, since in this case it made quite a bit of sense to impose hard stops on the mechanical linkage. In order to guarantee expected behavior, the potentiometer was used as a variable resistor in a negative feedback op-amp circuit. The reference voltage and current-setting resistor value were chosen so that the output would vary from approximately 0.5 V to approximately 4.5 V. In order to ensure that this entire range would be read by the A/D converter on-board the E128, a rail-to-rail op-amp was used.