How Does a Transducer
The easiest way to understand how a transducer functions is to think
of it as a speaker and a microphone built into one unit. A
transducer receives sequences of high-voltage electrical pulses
called transmit pulses from the echosounder. Just like the stereo
speakers at home, the transducer then converts the transmit pulses
into sound. The sound travels through the water as pressure waves.
When a wave strikes an object like a weed, a rock, a fish, or the
bottom, the wave is reflected. The wave is said to echo—just as
your voice will echo off a canyon wall. When the reflected sound
wave returns the transducer acts as a microphone. It receives the
sound wave during the time between each transmit pulse and converts
it back into electrical energy.
A transducer will spend
about 1% of its time transmitting and 99% of its time quietly
listening for echoes. Remember, however, that these periods of time
are measured in microseconds, so the time between pulses is very
short. The echosounder can calculate the time difference between a
transmit pulse and the return echo and then display this information
on the screen in a way that can be easily understood by the user.