Piezo transducers generator#
Piezo transducers driver#

HP 33120 15MHz Function/Arbitrary Waveform Generator Tektronix TDS3012 2-Channel Color Digital Phosphor Oscilloscope (100MHz, 1.25GS/s) The resultant total deflection will be the same for a bipolar signal of -2.5V to +2.5V as a single-ended signal of 0V to +5V.įigure 3. This unipolar deflection will be larger in amplitude from zero than when the bipolar signal was applied as in Figure 2. When a single-ended signal is applied, the PZT deflects one direction from the mechanical zero point. Figure 2 illustrates the mechanical deflection about a midpoint of mechanical zero when an audible PZT is driven with a bipolar signal.įigure 3 shows the mechanical deflection when a single-ended signal is used to drive the PZT. There are two possible ways to excite the audible PZT to produce sound by driving it with a single-ended signal (i.e., 0V to +5V) or with a bipolar signal (i.e., -2.5V to +2.5V). The brass plate is attached to a supporting ring, which is part of the molded plastic case, using a silicone adhesive. The other side of the piezoceramic plate becomes the second electrode contact. This side becomes one electrode connection. One side is bonded to a thin brass plate around the piezoceramic plate's circumference using an adhesive.

A piezoceramic plate is plated with silver on both sides. Structure of PZTsįigure 1 illustrates a cut-away view of a typical audible PZT. Three common PZTs manufactured by Mallory (North American Capacitor Company) were chosen for investigation of driving source impedance versus sound pressure, single and bipolar drive versus sound pressure, and PZT impedance characteristics. This can affect peak power supply capacity as well as filtering requirements. What Does the Impedance of a PZT Look Like? This can impact drive circuit complexity. Bipolar, with the Same Peak-to-Peak Amplitude? Is There Any Detectable Sound Pressure Difference when Driving an Audible PZT Single-Ended vs. This has a direct effect on the peak capacity of a power supply that is used for driving the PZT. Sound Pressure when Driving an Audible PZT? What Is the Effect of Source Impedance vs. However, there are a few important questions that cannot be answered directly from their data sheets. Manufacturers of piezo transducers publish curves and specifications concerning their respective devices. The relationship between source impedance and sound pressure level is measured, single-ended (S/E) and bridge-tied load (BTL) driving schemes are compared and the input impedance of a PZT is characterized.Īudible piezoelectric transducers (PZTs) are often used as warning devices or alarms.

Piezo transducers driver#

This audio application note identifies and describes the key elements in designing a driver for a piezoelectric transducer (PZT).