Good quality electrical connections are absolutely essential to device performance and longevity.  The engineering and technical assembly staff at APC International are experts at terminating connections to PZT and we are willing to share our expertise and accumulated knowledge and experience if necessary so please contact APC International with questions or for a review of your termination process.

There are several different methods one can utilize to make electrical connections to PZT components, and generally it starts with the electrode material on the PZT component and any special patterns or custom poling techniques.  Read on for a breakdown of the major considerations when connecting to PZT.  

Electrodes and Electrode Patterns:

APC also offers several "standard" electrode options to which the connections may be different.  Fired on silver is the electrode of choice for most people.  It's cost effective, relatively easy to work with, and is easily solderable.  For shear mode applications and select other custom applications, a heat cured silver epoxy is the best choice.  This material is NOT solderable but leads can be bonded to the surface using similar silver epoxies.  Lastly, nickel plating is a robust surface, can withstand certain extreme environments, and is solderable using the same techniques one would use when soldering to the standard silver electrodes. 

 

Additional Considerations and Types of Connections:

While considering the end use, housing, electrode pattern for ease of connection, etc. one must also ask, "How exactly are we going to make this connection to the piezo?"  The answer may depend greatly on several factors including part size and geometry, accessibility inside the housing, the environment involved, the shear volume of the parts in consideration (avoiding something like soldering when connecting to 1 million piezo elements would be beneficial both in cost and time) etc.  Another question you might ask could be "Do we need wires to make this connection?"  Connecting to the piezo can be as simple as bonding it to a conductive substrate using a conductive adhesive of some type, simply soldering wires, bonding leads using conductive silver epoxy, or as complicated as custom designing housings with electrodes inside using housing force to hold the piezo between two metal electrodes.  We will briefly touch on each.

 

Wire Selection:

Solid? Stranded? Gauge? Insulation type? Intrinsic Safety?  So many things to consider when thinking about selecting a wire for your application.  APC recommends the use of stranded wire for most applications.  This is due to the improved flexibility and higher conductance when compared to solid core wire.  When working with smaller PZT components (OD < .5" & Thk < .040") using typical power levels, lead sizes of 28 to 32 are typical.  For intrinsically safe applications, this may need to be increased to 26 gauge.  As the components get larger or the required power levels increase, 26 gauge, and even 24 gauge, may be used.  For applications where power requirements are small, or the components are very thin, a lead size of 32 gauge is the preference at APC.