We have already discussed the working of a velocity transducer and in the topic it was explained that velocity is a time derivation of displacement and displacement is the time integral of velocity. Similarly, we can also say that acceleration is the time derivative of velocity. Thus, a velocity transducer/sensor is enough to measure acceleration. All you have to do is add a differentiator circuit to the transducer. The figure of an acceleration transducer is shown below.
The figure shows a velocity transducer with a moving coil placed in between two magnetic poles. In order to obtain a linear motion, a pivot is placed on the surface that supports tye coil. This device can be used to find both linear as well as non-linear acceleration. The output voltage is obtained according to the motion of the coil inside the magnetic field. This output voltage is given as the input of a differentiator circuit. The output voltage of a differentiator can be written as
eoutput = einput (R/(R+(1/jwc))
Over the frequency range where the value of resistance R is very small in comparison with reactance 1/wc of the capacitor, the equation can be written as
eoutput = einput R/(R+(1/jwc))
= kv Sin (wt).jwCR
eoutput = kvw CR Cos (wt)
The equation shows that the output voltage is the time derivative of the input and leads the input by 90 degrees. Accordingly, the output voltage is a measure of the displacement.
Other Acceleration Transducers
Another commonly used acceleration transducer is the accelerometer. (Main Article: Accelerometer). This device is used to measure the measurable acceleration by an object instead of co-ordinate acceleration. A piezoelectric accelerometer is mostly used in industrial applications, where piezoelectric principle comes into work.Its other prototypes include Micro Electro-Mechanical System (MEMS) Accelerometer, Piezoresistive and capacitive Acceleromter and so on.