Inverse transducers

Transducers that work in a reverse mode are called inverse transducers or output transducers. Transducers which are used for the determination of nonelectrical parameters can be used as inverse transducers if they display superlative performance in its operation when the input and output quantities are reversed. This type of system is very much required when we have to convert variables like linear displacement, angular displacement, torque, force etc. to electrical signals. Here accuracy of feedback measuring systems is very important and significant and it depends on the characteristics of the physical system which is used for the conversion of the output signal into a signal of desirable form and dimensions for comparison by the comparator. The different quantities usually compared are torque, force, pressure and position. According to the quantity which is to be compared, feedback systems are designated as torque-balance, force-balance and position-balance systems. Voltages and currents take the place of variables in the case of electronic signal processing amplifiers. Some other systems like parallel-plate capacitor, moving coil assembly with permanent magnet and piezoelectric crystal are also employed in inverse transducers a feedback measuring systems. Here electrical output and the pneumatic bellows with mechanical output in pneumatic systems. A parallel plate capacitor and piezoelectric crystal converts displacements into proportional voltages. A moving coil assembly with permanent magnet converts dc current to proportional torque.