What is an accelerometer?
An accelerometer is an electromechanical device. Used to measure static or dynamic acceleration forces in an object. These forces can be simplified into three main types.
- Motion – this is usually defined as a “slow” change in position. Such as: up and down motion in a game, human movement and even a steady acceleration in position such as a rocket launching.
- Shock – this is a sudden change in acceleration. Such as: a car crash or drop testing.
- Vibration – a complete movement whether that be; side by side, up and down over a period of time. Such as Wind Turbine Monitoring, an electric motor and resonance detection.
How does it work?
An accelerometer works by measuring acceleration. However, not by calculating how speed changes over time but by measuring how the force or mass responds to the change in action.
A good example that everyone can relate to is how our body reacts when in a vehicle and the driver accelerates. It feels as though your body automatically pushes back into your seat. When the reality is your seat is trying to catch up to the change in speed which just occurred. Our body and brain and other senses – register the action like a type of accelerometer. The more force your body experiences; the more acceleration your brain registers from our body movements to those of the car. Other senses include the sound of the tyres on the road, engine sound and movement of objects outside. Therefore, we sense the changes in acceleration based on the senses recognised by the body.
Basically, Accelerometers work in a similar way.
What is an AC Response Accelerometer vs DC Response Accelerometer?
An AC Response Accelerometer means it is AC Coupled. This type is popular because they can measure dynamic events such as high speed vibration, modal analysis and high temperatures. They have a wide frequency response and high signal to noise ratio. AC Response Accelerometers don’t measure accelerations like gravity or sustained accelerations.
A DC Response Accelerometer is DC Coupled. It measures down to zero hertz which makes it ideal to measure static and dynamic acceleration such as shock. Accelerometers that don’t have a DC Response can delay a result. As it produces errors, especially over long event recordings.
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