An in-line dynamometer is a device used to measure the force or power output of a machine or engine. It is typically installed directly in the drive shaft or power transmission line, allowing for real-time measurement of torque and rotational speed. This data helps engineers and technicians assess the performance and efficiency of various mechanical systems. These dynamometers are commonly used in automotive testing, where they can evaluate the performance of engines and transmissions. By providing accurate measurements, in-line dynamometers assist in optimizing designs and ensuring that machines operate within their intended specifications.