so as a continuation of my research in piezoelectric effect i need a frequency source (electromagnetic shaker) to generate piezoelectric voltage. But my problem is i don't have a shaker. So my solution is to used an audio speaker to quantify the frequency but the question is does this thing work? is anyone here working with the audio speaker as shaker for piezoelectric application? how efficient is this compare to standard electromagnetic shaker? thanks!
The commercial electromagnetic shaker used to excite systems for purposes of identifying modes or transfer functions usually are a type of linear voice coil actuator so very similar to the actuator mechanism that drives a speaker cone. The difference in the commercial shakers is they are usually designed to handle much more current so that they can drive a higher peak force. Also the shakers are usually a part of a closed loop system, that is there are force or position transducers that sense the motion of the shaker and feed into a controller to insure that the motion of the shaker closely follows the intended command and spectrum of frequency or tone desired.
A piezoelectric device is usually very stiff and requires allot of force to excite. Although you can probably find a commercial electromagnetic shaker that will do the job, a speaker driver will likely not be able to. The stiffness of the piezo will arrest most of motion applied. So what you will wind up measuring is not the piezo, but rather a combination of the speaker-piezo system combined. In other words, it's a bad impedance match (mechanically).