A horn analyzer is a test instrument dedicated to determine the

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied Periodic function, periodic force (or a Fourier analysis, Fourier component of it) is equal or close to a natural frequency of the system ...

and

anti-resonance In the physics of coupled oscillators, antiresonance, by analogy with resonance, is a pronounced minimum in the amplitude of an oscillator at a particular frequency, accompanied by a large, abrupt shift in its oscillation phase. Such frequencies ...

frequencies of

ultrasonic Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

parts such as

transducer A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, measurement, and cont ...

s, converters, horns/

sonotrode In ultrasonic machining, welding and mixing, a sonotrode is a tool that creates ultrasonic vibrations and applies this vibrational energy to a gas, liquid, solid or tissue. A sonotrode usually consists of a stack of piezoelectric transducers a ...

s and acoustic stacks, which are used for

ultrasonic welding Ultrasonic welding is an industrial process whereby high-frequency ultrasonic acoustic vibrations are locally applied to work pieces being held together under pressure to create a solid-state weld. It is commonly used for plastics and metals, an ...

, cutting,

cleaning Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning is often performed for aesthetic, hygienic, functional, environmental, or safety purposes ...

, medical and industrial applications. In addition, digital horn analyzers are able to determine the

electrical impedance In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. Quantitatively, the impedance of a two-terminal circuit element is the ratio of the com ...

piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word '' ...

materials, the Butterworth-Van Dyke (BVD) equivalent circuit and the mechanical quality fator (Qm). Resultado de medição com um analisador de frequência de transdutores

Resultado de medição com um analisador de frequência de transdutores

Principles of operation

A digital horn analyzer performs a frequency sweep while monitoring the current flowing through the device under test, in order to detect the resonance and anti-resonance frequencies and their respective electrical impedances. The anti-resonance is the frequency at which the current encounters maximum impedance, and the resonance is the frequency of minimum impedance. In analog

microampere The ampere (, ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to elect ...

-meter-based horn analyzers, the user identifies the frequencies manually, using the meter to detect the points of minimum and maximum current while sweeping the driving frequency. In digital analyzers, frequency detection and impedance calculation are performed automatically through embedded software. Impedance analyzers can be used as advanced horn analyzers, but are not usually a cost-effective alternative for everyday industrial demands, due to their higher cost, larger size and greater complexity.

Applications

Horn analyzers are widely used by manufacturers of power ultrasonic equipment, to allow the proper tuning and quality control of sonotrodes, transducers and boosters. Horn analyzers are also employed by end-users for preventive and corrective maintenance.

Tuning

Accurate frequency tuning is indispensable for the proper use of power ultrasonic equipment. In an acoustic set, the parts act like narrow pass-band filters, and their central frequencies should be perfectly aligned to avoid heating losses and to improve energy transmission. Horn analyzers can be tuned to the desired frequency using a lathe or

milling machine Milling is the process of machining using rotary cutters to remove material by advancing a cutter into a workpiece. This may be done by varying direction on one or several axes, cutter head speed, and pressure. Milling covers a wide variety of d ...

by adjusting the part dimensions to the desired value.''Ultrasonic assembly of thermoplastic mounding and semi-finished products: Recommendations on methods, construction and applications''. ZVEI – Zentralverband Elektrotechnik- und Elektronik Industrie e.V. Fachverband Elektroschweissgeräte.

References

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External links

Example of a horn analyzer, including specifications
via ATCP Physical Engineering Ultrasound Industrial equipment Electronic test equipment