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Transducer current limiter circuit


New Member

I have designed a H-bridge circuit and it gives 300Vpeak_to_peak AC signal on the output. here is the schematic:

I want to drive an ultrasonic transducer by using this driver circuit. I have a quesiton for this operation.How can I limit my output current? I am using a 60W transducer and maybe it can be damaged because of the output current. Could you direct me, or share sample to add this limiter circuit?

with kind regards


Well-Known Member
Most Helpful Member
Do you have a datasheet for the transducer, that you could post.?


New Member
Do you have a datasheet for the transducer, that you could post.?
here is the information of my transducer:

Piezo Material: SM118
Body Material: Aluminum
Dimensions: 53.75 x 45 x 35 mm
Resonant frequency fr: 40 KHz±1 KHz
Maximum Output Power : 70W, alone, or 50W for parallel connection
Mechanical Q: 1000
Maximum allowable velocity :40 cm/s
Maximum allowable Temperature : 120 C
Resonant impedance Zm: ≤50 Ω
Static capacitance Cs: 4000pF ±10
Test Condition: 23±3 °C 40~70% R.H.
fr, Zm, Kp => Test voltage 1Vrms
Cs => LCR meter at 1KHz 1Vrms
Drawings: SMBLTD45F40H,
Applications: High-power ultrasonic applications such as ultrasonic cleaning tanks, ultrasonic plastic welding, ground sonar transducer, Bio Diesel mixer transducer, Solid separation transducer, stop organism growth on boat hull, Biodiesel mixing transducer, High-Torque Traveling Wave Ultrasonic Motor and others.
Notes: For the thickness of the ring transducer used (5.5mm), the maximum input voltage is 1,650V but the power output should not exceed 70W for single transducer or 50W for parallel setup. If the temperature is higher than 120C the transducer will depolarize and maybe fracture. So the operating voltage suggested is between 450-500V.


New Member
I want to limit AC current that flows on the transducer on the output stage. here is the schematic:

Last edited:

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