I am trying to drive a 120khz, 60W ultrasonic piezoelectric transducer. To do so I have an arduino mega2560 producing a 120khz frequency and am feeding that into the circuit to switch a TIP102 transistor. This transistor is feeding power to my transducer from a 12v power source. I intend to connect an inductor in parralel with the Transducer as this will amplify the output but will do so at a later time.
For now I am just trying to get any output at all. So far I have been unable to get the transducer to do anything. I am basing my (very simple) driving circuit on (full image found below), a schematic posted. My transducer is.
This paper investigates low cost matching network for high impedance ultrasonic transducers. Matching the output transmitter impedance to high impedance transducer is important to maximize the transfer of power and improve the transmitting efficiency of the transducer, and so achieve better signal-to-noise ratio.
The specs of the transducer are as follows. Frequency 120 KHz. Power 60W. resonate frequecy: 120±1.5 KHZ. capacitance: 4000 ±10% PF.
resonate impedance:=100MΩ Can someone please let me know what I am doing wrong here or what other avenues I should run down to get this working? Click to expand.D1 is there for the inductor.
Inductor causes voltage spikes and I assume having those pass backwards through the circuit is less than ideal. Now for the moment I don't have an inductor but adding it later, as well as the diode will happen. Mainly to protect the transistor. Is there not a transistor that will support switching 60watts at a high frequency like this? The most I have seen would require a higher base voltage than I am capable of having from my microcontroller. I am becoming quite sure that the transistor is just too slow.