US3328609A - Electrical energizing circuit for a piezoelectric element - Google Patents

Electrical energizing circuit for a piezoelectric element Download PDF

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Publication number
US3328609A
US3328609A US405151A US40515164A US3328609A US 3328609 A US3328609 A US 3328609A US 405151 A US405151 A US 405151A US 40515164 A US40515164 A US 40515164A US 3328609 A US3328609 A US 3328609A
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United States
Prior art keywords
transistor
circuit
crystal
resistor
piezoelectric element
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Expired - Lifetime
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US405151A
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English (en)
Inventor
Clicques Marcel
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Institut de Recherches de la Siderurgie Francaise IRSID
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Institut de Recherches de la Siderurgie Francaise IRSID
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B06B1/0215—Driving circuits for generating pulses, e.g. bursts of oscillations, envelopes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/30—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator
    • H03B5/32—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator
    • H03B5/36—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator active element in amplifier being semiconductor device
    • H03B5/362—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator active element in amplifier being semiconductor device the amplifier being a single transistor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B7/00—Generation of oscillations using active element having a negative resistance between two of its electrodes
    • H03B7/02—Generation of oscillations using active element having a negative resistance between two of its electrodes with frequency-determining element comprising lumped inductance and capacitance
    • H03B7/06—Generation of oscillations using active element having a negative resistance between two of its electrodes with frequency-determining element comprising lumped inductance and capacitance active element being semiconductor device
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/335—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of semiconductor devices with more than two electrodes and exhibiting avalanche effect
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/30—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups with electronic damping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/50—Application to a particular transducer type
    • B06B2201/55—Piezoelectric transducer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/70—Specific application

Definitions

  • This invention relates to an arrangement for electrically energizing piezoelectric transducers and their electrostrictive and magnetostrictive analogs, and particularly to an energizing circuit for transducers of the type employed to generate ultrasonic vibrations for testing the homogeneity of structual elements, and more particularly of metallic elements.
  • Another object is the provision of an energizing circuit for transducers of the type described which can be operated with a power supply of relatively low voltage.
  • a general object is the provision of energizing apparatus for transducers which is readily portable.
  • the electrical energizing arrangement for piezoelectric transducers and the like includes a transistor which is subject to avalanche breakdown, that is, having a characteristic collector current-voltage curve which has a portion of infinite slope adjacent another portion of negative slope.
  • the piezoelectric transducer is arranged in such a manner that the sudden potential drop caused by the transistor when it operates in avalanche breakdown is at least partly applied to the terminals of the transducer, directly or indirectly.
  • FIG. 1 shows a characteristic voltage vs. current curve of a transistor employed in this invention
  • FIG. 2 is a schematic of an energizing circuit for a piezoelectric transducer according to the invention
  • FIGS. 3 to 5 are schematics of modifying details for the circuit of FIG. 2;
  • FIG. 6 is a schematic showing another energizing circuit of the invention for a piezoelectric crystal.
  • transistors are suitable for such operation, and particularly those known as mesa transistors.
  • FIG. 1 shows the current I in the collector circuit of such a transistor as the function of the potential V applied to the collector and emitter of the transistor when the base-emitter potential has a value sufficient normally to block the transistor, this value being positive, zero, or slightly negative for a P-N-P transistor, and negative, zero, or slightly positive for an N-P-N transistor.
  • the characteristic curve of the transistor has a slope a l /dV which is infinite (at the point A), and an adjacent portion of the curve, indicated by a broken line, has a negative slope.
  • the abrupt potential drop at a transistor which is in a condition of avalanche breakdown is applied to a crystal employed as a transducer.
  • the terminals 9 and 10 of the crystal transducer 1 are respectively connected to the grounded base lead 6 and the collector 2 of the transistor 3 which is of the N-P-N type.
  • the collector is supplied with voltage from the positive terminal of a battery 4 through a resistor 5.
  • the emitter 7 of the transistor 3 is grounded through a resistor 8.
  • the apparatus represented by the schematic of FIG. 2 operates as follows:
  • the transistor is initially blocked since its base is at ground potential.
  • the battery 4 gradually charges the capacitor constituted by the crystal 1 through the resistor 5.
  • avalanche breakdown of the transistor causes discharge of the crystal charge, and the discharge current increases in magnitude as the potential between collector and emitter decreases,
  • Point B in FIG. 1 represents the condition of the transistor at this stage.
  • a new cycle begins with the charging of the crystal 1 by the battery 4.
  • the vibrations of the crystal may be damped either by known mechanical means, or electrically by shunting the terminals 9, lit with a damping circuit.
  • FIGS. 3 and 4 Two damping circuits are diagrammatically illustrated n FIGS. 3 and 4 which only show the terminals 9 and 10 of the circuit of FIG. 2.
  • the damping circuit of FIG. 3 consists solely of a resistor 11 in series with a capacitor 12 whose capacitance is much smaller than that of the crystal 1 and offers only low impedance at the resonant frequency of the latter.
  • the circuit of FIG. 4 includes an inductance 13 arranged in series with the resistor 11' and the capacitor 12'.
  • the crystal 1 is linked with an amplifier and a load, jointly indicated by numeral 14, by a coaxial cable 15 suitably terminated in its characteristic impedance at its output terminals by resistor 16.
  • the resistor 16 is arranged in series with a capacitor 17 in order not to interfere with the charging of the crystal 1 by the battery '4. In this arrangement, the resistor 16 may function in the same manner as the damping resistor 11 in the circuit of FIG. 3.
  • the crystal 1' is conductively interposed between the emitter 7 of the transistor 3 and ground.
  • a capacitor 18 is arranged between the collector 2 and ground.
  • the battery 4 provides potential to the collector of the transistor 3, which is of the N-P-N type, through a resistor 5' and the coaxial line 15 which is terminated by resistor 16 and is suitable for transmitting electrical signals developed by the crystal 1 to the load 14 when the crystal operates as a receiver.
  • the base 6 of the transistor 1 is grounded through a variable resistor 19 which is negatively biased by a battery 20, whereby the return of the transistor to its blocked state is accelerated.
  • the advantage of the modified circuit of FIG. 6 over the circuit of FIG. 2 resides in the fact that the adapting resistor 16 may be arranged directly in parallel with the crystal 1 without the need for a capacitor as shown at 17 in FIG. 5 since the charging circuit of the capacitor 18 is separated from the crystal 1 when the transistor is in the non-conducting state. Moreover, the resistor 16 may simultaneously function as a damping resistor for the vibrations generated by the crystal. On the other hand, the circuit of FIG. 6 does not permit total use of the voltage drop from V to V in the collector circuit.
  • the portion of the sudden potential drop V V which is effectively applied to the terminals of the crystal 1' in the device of FIG. 6 may be calculated from the equation wherein C is the capacitance of the crystal 1, C is that of the capacitor 18, V is the potential at the terminals of the crystal 1 after avalanche breakdown of the transistor 3.
  • the equation is derived from the fact that the charges before and after avalanche breakdown are equal, when disregarding the very small charge which flows through the resistor 16 during the brief period of avalanche breakdown:
  • V /(V V approaches unity when C is increased or C is reduced. It is therefore desirable to make the capacitance C of the capacitor 18 much larger than that of the crystal 1.
  • a resistor 8 may be employed for limiting the current released by the transistor 3.
  • the same object is achieved in the circuit of FIG. 6 by the insertion of the inductance 23 in the discharge circuit of the capacitor 18, either in the collector lead, as illustrated, or in the emitter lead. This arrangement has the following advantage:
  • the discontinuous emission of ultrasonic signals be repeated at brief intervals, it is necessary, for a given set of capacitance values, that either the resistance of the element 5 be reduced or the voltage of the battery 4 be increased.
  • the first-mentioned change is simple, but the resistance of the resistor 5 should be sufiicient to ensure that the strength of the current which passes after avalanche breakdown be located below the point A in the characteristic curve of FIG. 1. If this would not otherwise be the case, the inductance 23 has a necessary corrective effect.
  • Embodiments of the invention represented by the circuits of FIGS. 2 and 6 have been successfully operated for discontinuous emission of ultrasonic vibrations with a battery 4 of only volts and with a silicon mesa transistor 3 or 3 of N-P-N type commercially available as type 2N'706A (Texas Instrument Company).
  • the crystals 1, 1 each consisted of barium titanate, and had a capacitance of 10,000 picofarads, resonant at 4 megahertzs.
  • the coaxial cable 15 was 15 meters long and had an impedance characteristic of 150 ohms.
  • the amplifier 14 was constituted by a conventional band pass amplifier centered on the frequency of the crystal and having 1 MHz bandwith. The cable was feeding on its characteristic resistance.
  • the pulse generator 22 was a 10-volt generator of positive pulses, having a pulse time of 0.05 microsecond.
  • the voltages of batteries at 20 and 4 were respectively10 volts and 4 volts.
  • the energizing circuit of the invention requires little space and its weight can be so small that the entire apparatus becomes readily portable. It can be constructed at low cost. Because of the shortness of the excitation and the close spacing between crystal and transistor possible in the devices of the invention, the efficiency is excellent.
  • Apparatus for periodic generation of ultrasonic energy comprising:
  • second circuit means connected to said transistor and adapted to be connected to a piezoelectric element for applying at least a portion of the potential drop occurring at said transistor during said breakdown to said piezoelectric element.
  • said transistor is of the N-P-N type
  • said second circuit means are adapted for conductively interposing said piezoelectric element between the collector of said transistor and ground
  • the first circuit means including two resistors, said collector being connected to said source through one of said resistors, the emitter of said transistor being connected to ground through the other resistor, and the base of said transistor being directly connected to ground.
  • said transistor is of the type N-P-N
  • said second circuit means are adapted for conductively interposing said piezoelectric element between the emitter of said transistor and ground
  • said first circuit means including a resistor and a capacitor, the collector of said transistor being connected to said source through said resistor and being connected to ground through said capacitor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Oscillators With Electromechanical Resonators (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Apparatuses For Generation Of Mechanical Vibrations (AREA)
US405151A 1963-10-24 1964-10-20 Electrical energizing circuit for a piezoelectric element Expired - Lifetime US3328609A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR951686A FR1380730A (fr) 1963-10-24 1963-10-24 Perfectionnements apportés aux dispositifs pour exciter électriquement des éléments piézoélectriques

Publications (1)

Publication Number Publication Date
US3328609A true US3328609A (en) 1967-06-27

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US405151A Expired - Lifetime US3328609A (en) 1963-10-24 1964-10-20 Electrical energizing circuit for a piezoelectric element

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US (1) US3328609A (xx)
AT (1) AT254547B (xx)
BE (1) BE654317A (xx)
DE (1) DE1238702B (xx)
FR (1) FR1380730A (xx)
GB (1) GB1034249A (xx)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3416036A (en) * 1967-01-13 1968-12-10 Hughes Aircraft Co Integrated crystal circuits and the method of making thereof
US3541838A (en) * 1968-08-01 1970-11-24 Blackstone Corp Methods and apparatus for testing glassware
US3581125A (en) * 1969-09-30 1971-05-25 Clevite Corp Oscillator circuit for ultrasonic apparatus
US3984704A (en) * 1974-01-25 1976-10-05 Agence Nationale De Valorisation De La Recherche (Anvar) Device for correcting the frequency response of an electromechanical transducer
US4004165A (en) * 1973-03-27 1977-01-18 European Atomic Energy Community (Euratom) Ultrasonic signal generators
US4653101A (en) * 1984-03-27 1987-03-24 William Beith Audio reverberator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007008505A1 (de) * 2007-02-21 2008-08-28 Siemens Ag Verfahren zum Betreiben eines piezoelektrischen Wandlers und Wandlervorrichtung

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562450A (en) * 1947-07-05 1951-07-31 Sperry Prod Inc Pulse cutoff device
US2594841A (en) * 1945-08-11 1952-04-29 Brush Dev Co Piezoelectric transducer with pushpull and feedback circuit
US2692337A (en) * 1948-12-29 1954-10-19 Bell Telephone Labor Inc Oscillation generator
US2825813A (en) * 1955-07-12 1958-03-04 Emerson Radio & Phonograph Cor Temperature-compensated transistor oscillator circuit
US2852676A (en) * 1955-02-15 1958-09-16 Ivan L Joy Voltage train generating device
GB814185A (en) * 1956-06-12 1959-06-03 Nat Res Dev Transistor circuits
US3080489A (en) * 1960-12-27 1963-03-05 Bell Telephone Labor Inc Pulse generator circuit employing diode and inductor to reduce cycle time
US3141981A (en) * 1962-07-03 1964-07-21 Henebry William Michael Pulse generating circuit having a high repetition rate utilizing avalanche transistor-coaxial line combination
US3200350A (en) * 1961-09-15 1965-08-10 Hazeltine Research Inc Ringing circuit with means preventing damped oscillations
US3225313A (en) * 1963-04-12 1965-12-21 Collins Radio Co Pulse triggered vhf crystal controlled oscillator
US3258720A (en) * 1966-06-28 Self-tuning harmonic-mode crystal oscillator circuit

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258720A (en) * 1966-06-28 Self-tuning harmonic-mode crystal oscillator circuit
US2594841A (en) * 1945-08-11 1952-04-29 Brush Dev Co Piezoelectric transducer with pushpull and feedback circuit
US2562450A (en) * 1947-07-05 1951-07-31 Sperry Prod Inc Pulse cutoff device
US2692337A (en) * 1948-12-29 1954-10-19 Bell Telephone Labor Inc Oscillation generator
US2852676A (en) * 1955-02-15 1958-09-16 Ivan L Joy Voltage train generating device
US2825813A (en) * 1955-07-12 1958-03-04 Emerson Radio & Phonograph Cor Temperature-compensated transistor oscillator circuit
GB814185A (en) * 1956-06-12 1959-06-03 Nat Res Dev Transistor circuits
US3080489A (en) * 1960-12-27 1963-03-05 Bell Telephone Labor Inc Pulse generator circuit employing diode and inductor to reduce cycle time
US3200350A (en) * 1961-09-15 1965-08-10 Hazeltine Research Inc Ringing circuit with means preventing damped oscillations
US3141981A (en) * 1962-07-03 1964-07-21 Henebry William Michael Pulse generating circuit having a high repetition rate utilizing avalanche transistor-coaxial line combination
US3225313A (en) * 1963-04-12 1965-12-21 Collins Radio Co Pulse triggered vhf crystal controlled oscillator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3416036A (en) * 1967-01-13 1968-12-10 Hughes Aircraft Co Integrated crystal circuits and the method of making thereof
US3541838A (en) * 1968-08-01 1970-11-24 Blackstone Corp Methods and apparatus for testing glassware
US3581125A (en) * 1969-09-30 1971-05-25 Clevite Corp Oscillator circuit for ultrasonic apparatus
US4004165A (en) * 1973-03-27 1977-01-18 European Atomic Energy Community (Euratom) Ultrasonic signal generators
US3984704A (en) * 1974-01-25 1976-10-05 Agence Nationale De Valorisation De La Recherche (Anvar) Device for correcting the frequency response of an electromechanical transducer
US4653101A (en) * 1984-03-27 1987-03-24 William Beith Audio reverberator

Also Published As

Publication number Publication date
DE1238702C2 (xx) 1967-10-19
AT254547B (de) 1967-05-26
FR1380730A (fr) 1964-12-04
GB1034249A (en) 1966-06-29
DE1238702B (de) 1967-04-13
BE654317A (xx) 1965-02-01

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