Final answer:
The lowest speed that auto throttles will allow you to set is typically the stall speed, which is the minimum speed required to maintain stable flight.
Step-by-step explanation:
The lowest speed that auto throttles will allow you to set can vary depending on the specific aircraft and its system capabilities. However, in general, the lowest speed that auto throttles will allow is typically the minimum speed required to maintain stable flight, also known as the stall speed.
Stall speed is the minimum speed at which an aircraft can maintain lift, and it varies based on factors such as weight, configuration, and altitude. Auto throttle systems are designed to prevent the aircraft from flying below this critical speed to ensure safe operation.
For example, in a commercial airliner, the auto throttle system will prevent the pilot from setting the throttle to a speed below the aircraft's stall speed, which could lead to a loss of lift and a stall.