Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
A transducer is any device that convert one form of energy to another.
There are various kinds of transducers. In transducers, physical laws are applied to obtain desired results.
Examples of transducers are as follows:
1) Carbon Granule Microphones: Sound waves cause the vibration of a packet of carbon granules such that the resistance of th granules is varied according to the sound and the current passing through the packet is similarly varied.
2) Loud Speaker: Electrical signals are passed through a coil and thus a field is generated which causes the vibration of a diaphragm and thus generates sound waves.
Both of the above implement Faraday's and Lenz's Laws of Electromagnetism.
3) Electric Motor: Electricity is passed through a coil in the vicinity of a magnetic field and the coil rotates in the field according to Fleming's Left Hand rule.
4) Electric Generator (Dynamo): A coil is rotated in th vicinity of an electric field and thus a voltage is generated at the terminals of the coil according to Fleming's Right Hand rule.
5) Electric Light Bulb: Electric current passing through the element (tungsten) causes the excitation of electrons. When such electrons return to ground state, they emit light and heat.
There are so many other examples of transducers: Piezoelctric crystals, heating coils, antennas etc etc. I hope that this little reply of mine will at least give you a foundational idea so that your research can be properly directed.
You may not get a complete treatise on all kinds of transducers in one write-up ( the world is full of them) so you may need to browse the web or consult textbooks about specific types.