High-power, underwater transducers utilizing polarized piezoelectric ceramic material are usually limited in drive amplitude so that depolarization does not occur, but application of a dc bias field in the polarization direction allows the use of higher ac drive fields. To demonstrate the feasibility of biased operation as a means of achieving higher power, a thin-walled, spherical-shell transducer was constructed of Channel 5800 and tested in NUWC's Acoustic Pressure Tank Facility at a hydrostatic pressure of 1400 psig ͑9.65 MPa͒. The transducer was successfully driven to 33 V/mil ͑1.3 MV/m͒ rms with an accompanying bias field of 31 V/mil ͑1.2 MV/m͒. The source level was 206 dB re: 1 Pa•m at 61 kHz, corresponding to a 10-dB improvement over the unbiased drive limit of 10 V/mil ͑0.4 MV/m͒ rms and 196 dB re: 1 Pa•m.

High-power, underwater transducers using polarized piezoelectric ceramic material are usually limited in drive amplitude so that depolarization does not occur, but application of a dc bias field in the polarization direction allows the use of higher ac drive fields. To demonstrate the feasibility of a biased operation as a means of achieving higher power, a thin-walled, spherical-shell transducer was constructed of Channel 5800 and tested in NUWC’s Acoustic Pressure Tank Facility. The transducer was successfully driven to 33 V/mil (1.3 MV/m) rms with an accompanying bias field of 31 V/mil (1.2 MV/m) and a hydrostatic pressure of 1400 psig (9.65 MPa). The source level was 206 dB//mPa-m at 61 kHz, corresponding to a 10-dB improvement over the usual Navy standard unbiased drive limit of 10 V/mil (0.4 MV/m) rms. [Work supported by ONR.]