This is a piezo disc. It is 35mm in diameter. It can be used in conjunction with
Marshmallow DIY preamp to make The World's Greatest™ contact microphone.
Note that this disc does not have lead wires attached, so you will have to solder your own on. You will have to solder one wire to the outer brass rim of the disc. By convention, this wire is normally considered the ground or negative part of the disc. You have to solder another wire to the inner gray part of the disc. This part of the disc burns away very easily, so it is recommended to tin the wire and the iron, and then solder the wire on as quickly as possible. By convention this is usually considered the the positive part of the disc.
We also sell a
20mm disc with lead wires already attached.
Note that
the Marshmallow DIY Kit already includes a piezo disc.
