Abstract: A triboelectric device includes a voltage source, a polarizing amplifier, and electrodes to apply a polarizing voltage to a first material of the device. The electrodes are not fixed to the first material, allowing relative rubbing displacement between the electrodes and the first material. Preferably, a conductive second material, such as petrolatum, is provided between the first material and the electrodes. Such a device can have its properties change while in service. To accommodate this, the voltage source preferably provides an adjustable polarization voltage. The triboelectric device is useful as a transducer, and particularly useful as a hydrophone used in sonar antenna, as its mode type can be changed in the field during service to correct spurious signals or interferring noises.