USED for measuring the torque and brake power required to operate a driven machine. It has a device to MEASURE the frictional resistance. Following are the TWO types of dynamometers, used for measuring the brake power of an engine.Absorption dynamometers: The ENTIRE energy or power produced by the engine is absorbed by the friction resistances of the brake and is transformed into heat, during the process of measurement.Example: Prony brake dynamometer, ROPE brake dynamometer, Hydraulic dynamometer Transmission dynamometers: The energy is not wasted in friction but is used for doing work. The energy or power produced by the engine is transmitted through the dynamometer to some other machines where the power developed is suitably measured.Example: Epicyclic-train dynamometer, Belt transmission dynamometer, Torsion dynamometer.