Its inventor, Charles Babbage, is also known as the ?Father of Computing.

There are basically two types of dynamometers: the first one is bolted directly to an engine, and it's called engine dyno, while the second type of dynamometer can measure power and torque without removing the engine from the frame of the vehicle, and it's known as a chassis dyno.

An engine dynamometer measures power and torque directly from the engine's crankshaft (or flywheel), when the engine is removed from the vehicle. These dynos don't take in consideration power losses in the drive train, such as the gearbox, transmission or differential.

A chassis dynamometer measures power from the engine directly through the wheels. The vehicle is parked on rollers and the output is measured. These dynos can be fixed or portable.

The dynamometer works by applying various loads on the engine and by measuring the engine's ability to move the load. It is connected to a computer which uses mathematics to calculate the output of the engine. The engine is run from idle to its maximum RPM and the output is measured and interpreted on a graphic. Nearly all aspects of engine operation can be measured during a dyno run.

Generally, dynamometers are useful in the development and refinement of modern day engine technology. The concept is to use a dyno to measure and compare power transfer at different points on a vehicle, thus allowing the engine or drive train to be altered, in order to get a more efficient power transfer. For example, if an engine dynamo shows that a particular engine achieves 400 N'm (300 lbf'ft) of torque, and a chassis dynamo shows only 350 N'm (260 lbf'ft), it means that in order to recover the power loss, the drive train should be inspected and improved for maximum efficiency.

Dynamometers are typically expensive pieces of equipment, reserved for certain fields that rely on them for a particular purpose.

They are very handy, as they can diagnose the entire way a car is functioning, but they are sometimes unaffordable.