What is a transducer? What are the differences between an active and passive transducer?

A transducer is the electronic device which use converts a signal from one form of energy to another form of the energy.

The differences between active and passive transducers are:

An active transducer produce output without use of any external power source, whereas an passive transducer requires external power source for its working.

The resolution of a passive transducer is higher than an active transducer.

The design of passive transducer is much complicated than an active transducer.