The 50 kHz signal generated by this circuit is applied to a low impedance inductive transducer. A power PNP transistor like the TIP32 can be used in the driver stage sourcing some watts to a 4 to 8 Ω transducer. The frequency can be changed by the capacitor C2. Values in the range between 1 nF and 4n7 can be used. Current drain is about 500 mA, but more power can be obtained using a power MOSFET. Figure bellow shows the simulation in the MultiSIM. The waveshapes for the signal in the transducers are displayed by the virtual oscilloscope found in the MultiSIM.