Electromechanical transducers transform pressure into electrical quantities. They can be divided into several groups: resistance; induction; capacity; and piezoelectric transducers.
- Resistance transducers are based on – the change in resistance of a conductor due to their change in shape.
- Induction transducers are based on – the coil self-inductivity changes depending on the position of its core
- Capacity transducers are based on – the deformation of two plates which affects the capacity.
- Piezoelectric transducers are based on – shifts of ion electric charges in a crystal (anisotropic crystals, such as SiO2), which manifest as an electric voltage across the crystal or a membrane. The voltage is directly proportional to the pressure. The reverse piezoelectric phenomenon – electric voltage applied to piezoelectric material – can cause the material to undergo mechanical deformation. This is used to produce ultrasound.
Notes compiled by Andrei Cociug.