I got some different sizes piezo discs to experiment with, but there's one size that has 2 zones on the ceramic plate on top. I found out that they are called 3 contact piezos. Where do i solder my hot lead? The big surface or the small bit?
Thanks in advance!
It is a Self Oscillating piezo (used for sirens I think - if you google self oscillating piezo you can check out a datasheet if you want more info) it will work like a normal piezo pickup - wire one earth/ground wire to the metal base and two hots one to each of the two white bits on top.