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I would like to know what is the current consumed by a 1-2MHz Ultrasonic Sensor (i.e sensors used for Clamp on Ultrasonic flowmeter) to generate Ultrasound waves. The two ultrasonic sensor specifications I've found (see below), do not mention the current current consumed, why is it ? when I've enquired with one supplier I've found that they were not sure either.

Sensor Specification 1: Specification 1,

Sensor Specification 2: Specification 2

Edited Title of my question

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  • \$\begingroup\$ usually up to 100ma peak, make sure your supply can handle that, and put a bunch of various capacity capacitors nearby the power input pin of the device. \$\endgroup\$
    – KyranF
    Commented Sep 17, 2014 at 14:12

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These are bare piezoelectric elements so they can be used as transmitters and/or receivers. There is no impedance specified for the first sensor although the nominal driving voltage is specified as 1-10 V peak-to-peak. At the resonant frequency, I would expect the impedance to be on the order of 100 ohms. In that case, the driving current would be in the range of 10 to 100 ma peak-to-peak. Unfortunately, for a better value you would have to actual drive the sensor and measure the current or measure the impedance at the resonant frequency. For the second sensor, the capacitance is specified as 1800 pf and the parallel impedance as 60 ohms. The static capacitance is the value of the intrinsic capacitance due to its being made of ceramic. The parallel impedance is the impedance due to the resonance of the element. 1800 pf at 2 MHz has a reactance of 44 ohms. You can use the parallel combination of this with the 60 ohms to get a reasonable estimate of the overall impedance at resonance. Then the current can be calculated with ohms law. However, again, measuring the current on an actual sensor is the most accurate method.

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Ultrasonic sensors are piezoelectric devices that generate charge when deformed. They don't even need to be powered. You'd use a high input impedance amplifier or a charge amplifier to measure the signal.

They also deform when you apply a charge to generate ultrasound waves, but a "sensor" wouldn't necessarily be used in that mode.

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  • \$\begingroup\$ Thanks for your answer, I could have been more specific in my question, therefore edited my question to What is the current consumed by Ultrasonic Transducers (1-2MHz) to generate Ultrasound waves i.e what is minimum current consumed in milliAmperes ? \$\endgroup\$
    – Pravi
    Commented Sep 17, 2014 at 14:47

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