US3801799A - Capacitance and resistance-responsive control circuits - Google Patents

Capacitance and resistance-responsive control circuits Download PDF

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Publication number
US3801799A
US3801799A US00280219A US3801799DA US3801799A US 3801799 A US3801799 A US 3801799A US 00280219 A US00280219 A US 00280219A US 3801799D A US3801799D A US 3801799DA US 3801799 A US3801799 A US 3801799A
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circuit
circuit according
operative
oscillations
interpulse
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US00280219A
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C Atkins
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Cooper Industries LLC
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Wagner Electric Corp
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Assigned to STUDEBAKER-WORTHINGTON, INC. reassignment STUDEBAKER-WORTHINGTON, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WAGNER ELECTRIC CORPORATION
Assigned to EDISON INTERNATONAL, INC. reassignment EDISON INTERNATONAL, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: STUDEBAKER-WORTHINGTON, INC., A CORP. OF DE
Assigned to COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEXAS 77002, A CORP. OF reassignment COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEXAS 77002, A CORP. OF ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: EDISON INTERNATIONAL, INC., A CORP. OF DE.
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches

Definitions

  • ABSTRACT Control circuits for sensing and responding to impedance changes caused by a mammal in contact with or in proximity to an antenna or other sensor.
  • Each circuit includes at least one tuned circuit which is periodically energized to cause it to ring at its natural frequency, i.e., to produce damped oscillations.
  • Each tuned circuit includes an antenna or other sensor by which an external impedance is coupled to the tuned circuit.
  • the oscillations in the tuned circuit are attenuated to a degree determined by the capacitive and resistive components of the external impedance.
  • the resistive component is substantial and causes a marked change in the amplitude and duration of the damped oscillations in the tuned circuit, which are then enhanced and/0r detected to produce a predetermined control signal.
  • the present invention may advantageously incorporate the HIGH-DISCRIMINATION ANTENNA ARRAY FOR CAPAClTANCE-RESPONSIVE CIR- CUITS disclosed and claimed in U. S. Pat. No. 3,740,567 issued June 19, 1973 upon copending application Ser. No. 245,799 filed on Apr. 20, 1972 in the name of Carl E. Atkins.
  • the present invention advantageously incorporates a modified form of the circuits disclosed and claimed in copending application Ser. No. 255,155 entitled ELECTRONIC TIMING CIR- CUITS filed on May 19, 1972 in the name of Paul A. Carlson.
  • the present invention relates to capacitance and resistance responsive control circuitry.
  • condition-responsive circuits may be found in the prior art; see, for example, the following U.S. Pat. Nos.:
  • circuits embodying the invention are readily adaptable to a wide variety of uses, e.g., in plumbing control systems. Because of the superior sensitivity of the tuned circuit to loading by humans, an antenna with an exposed surface area of only a few square inches may be used which is smaller than any previously employed antenna area.
  • the present invention is embodied in and carried out by a condition-responsive control circuit in which at least one tuned circuit is periodically energized by pulses from a pulse generator and permitted to ring (oscillate) at its natural frequency during each interpulse null, whereby the change in the amplitude and/or duration of oscillations of the tuned circuit caused by coupling of an external impedance having a substantial capacitive or resistive component to the tuned circuit isenhanced and/or detected to generate a control signal.
  • the change in the amplitude of the damped oscillations may be enhanced before detection by providing an oscillator circuit which is shock excited into oscillation by the positive amplitude of the damped oscillations.
  • the oscillator circuit will provide an oscillatory output when the positive amplitude of the damped oscillations in the tuned circuit is above a predetermined threshold, and no oscillatory output when the positive amplitude is below that predetermined threshold.
  • the oscillating or non-oscillating output may then be detected to provide a control signal.
  • FIG. 1' is a schematic circuit diagram showing a first embodiment of the invention
  • Detector 18 is connected to tuned circuit 1410 detect v arjations in thearnplitude and/or duration of the damped oscillations which form the outpiit of the tuned circuit 14; H, W W
  • Pulse generator 10 supplies periodic pulses of positive polarity. to bias circuit 12', preferably in the frequency rangeof 10-20 KHz with a duty cycle of50%,
  • resistance R1 and capacitance C 1 are chosen so that diode D1 remainsback-biased during the interpulse null.
  • Resistance R1 and capacitance Cl may be replaced by a short circuit if the output of pulse generator 10 goes negative instead of being at approximately ground po- I tential between positive-going pulses.
  • the amplitude, frequency, and duration of the damped oscillations of tuned circuit 14 are relatively fixed and detector 18 is designed not to respond.
  • the Q of tuned circuit 14 is reduced, thereby sharply reducing the amplitude and/or duration of oscillations of the tuned circuit 14.
  • An inanimate object, which in most cases does not possess a substantial resistive component, has little or no effect upon the Q of the tuned circuit 14 and, consequently, little or no effect on the amplitude and/or duration of oscillations of the tuned circuit 14.
  • aload having a complex impedance with a substantial capacitive component is similarly capable of attenuating oscillations in the tuned circuit 14. when coupled thereto through sensor '16.
  • the circuit shown comprises a pulse generator 20 of the type disclosed and claimed in cross-referenced application Ser.
  • Detector 34 comprises limiting resistances R12 and R13 and detecting transistor Q5, and operates to provide a control signal to load circuits 38 and 40 in response to a predetermined output signal from enhancing circuit 30.
  • the output of transistor ()3 taken at its emitter oscillates with a positive DC component when tuned circuit 26 rings at sufficient amplitude, and is at approximately ground potential when the amplitude of the ringing is insufficient to cause oscillation and when the relatively small amplitude of positive pulse from pulse generator 20 is present.
  • the amplitude of the ringing of tuned circuit 26 will be sufficiently reduced to prevent oscillation of transistor 03 when a complex impedance load with a substantial capacitive or resistive component is capacitively coupled at antenna Al.
  • the reduction in amplitude of the damped oscillations of tuned circuit 26 is enhanced at the emitter output of transistor O3 to provide a change going from a periodic oscillatory output combined with a DC component to a non'oscillatory output at approximately ground potential.
  • Detector 34 comprising resistances R12 and R13, and transistor Q5 detects the presence and absence of oscillations at the output of the enhancing circuit 30, and generates a corresponding control signal.
  • Resistance R12 limits the base current and resistance R13 limits the collector current of transistor Q5.
  • transistor O5 is turned on by the DC component of the oscillation forcing the collector of transistor O5 to approximately ground potential.
  • transistor ()3 ceases to oscillate, with its emitter going to approximately ground potential, indicating loading of tuned circuit 26, transistor O5 is turned off and its collector rises to the supply voltage (approximately volts DC).
  • antenna A1 when antenna A1 is coupled to an impedance having either a substantial capacitive component, or a substantial resistive component such as is presented by humans and other mammals, a control signal of supply voltage is generated at the collector of transistor Q5; otherwise the control signal is at approximatelytl ground potential.
  • FIG. 3 another embodiment of a detector 44 is shown, a portion of which is peak detector 46.
  • the output of the peak detector is taken at the junction of diode D4, capacitance C12 and resistance R18.
  • the negative portions of the damped oscillation of the tuned circuit 14 turn off transistor Q7, causing a controlled quantity of charge to be supplied to capacitance C12 through resistance R17 and diode D4.
  • the value of resistance R18 is chosen to prevent capacitance C12 from discharging between positive portions of the damped oscillation of tuned circuit 14.
  • diode D4, capacitance C12 and resistance R18 function as a peak detector maintaining a detector output voltage approximately equal to the supply voltage.
  • a load circuit including a plate adapted for selective coupling with either antennae Al and A2.
  • a load circuit could be incorporated into an article worn by a person, such as a ring or a watchband, and used as a key to cause a control circuit to open a lock, for example.
  • the output of any or all of the detector circuits could be altered by the addition of a polarity inverter circuit.
  • a negative voltage could be provided by poling diode D4 in a manner opposite to that shown.
  • the resistive impedance for loading the tuned circuit may be ohmically coupled to the sensor or antenna, rather than capacitively coupled.
  • first means operative to generate energizing pulses
  • circuit according to claim 1 further comprising enhancing means operative'to enhance said interpulse oscillations of said second means.
  • said enhancing means comprises an oscillator circuit responsive to changes in the interpulse oscillations of said second means.
  • circuit according to claim 4 further comprising detection means operative to detect said interpulse oscillations of said second means after enhancement by said enhancing means and to generate a predetermined control signal in response thereto.
  • said detection means comprises a transistor circuit which is switched between conduction and non-conduction by the output of said enhancing means.
  • pulse generator means operative to generate an energizing voltage having alternating positive-going portions and approximately ground potential portions
  • bias means comprises a capacitance and resistance connected in parallel, and a blocking diode connected in series with said parallel-connected resistance and capacitance.
  • pulse generator means operative to generate an energizing voltage having alternating positive-going portions and negative-going portions
  • first signal channel means operative to receive said energizing voltage, and to sense the coupling of an external impedance having a substantial capacitive or resistive component and to generate a predetermined output signal in response thereto;
  • bias means operative to generate a negative signal between each positive-going portion of said energizing voltage
  • a tuned circuit operative to receive the output of said bias means and including a sensor by means of which said coupling of external impedances is effected;
  • enhancing means operative to receive and amplify the output of said tuned circuit; and v 4. detection means operative to detect the output of said enhancing means and to generate said predetermined control signal in response thereto.
  • circuit according to claim 14 further comprising a first load circuit controlled by said first signal channel means and a second load circuit controlled by said second signal channel means.
  • circuit according to claim 16 further comprising a third load circuit controlled by both said first and second signal channel means.
  • said first means comprises:
  • bias means operative to generate a positive signal during said interpulse periods during which said energizing voltage is at approximately ground potential.
  • a bias circuit comprising a first resistance and a first capacitance connected in parallel with one another and in series between the output of said pulse 3 ,80 1 ,799 g 9 l generator and one terminal of a stored-charge dia substantial capacitive or resistive component to said antenna by attenuating said oscillations; a tund ell-cult compnsmg an Inductance; a Second 4. a shock-excited oscillator connected to said tuned capacitance and an antenna connected in parallel circuit; and
  • a detector circuit for generating a control signal in produce oscillations during the time periods beresponse to a Predetermmed output Signal from tween pulses from said pulse generator, and to said i atorsense the coupling of an external impedance having

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  • Electronic Switches (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Dc-Dc Converters (AREA)
US00280219A 1972-08-14 1972-08-14 Capacitance and resistance-responsive control circuits Expired - Lifetime US3801799A (en)

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US28021972A 1972-08-14 1972-08-14

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US (1) US3801799A (de)
JP (1) JPS4959277A (de)
CA (1) CA1008145A (de)
DE (1) DE2341161A1 (de)
FR (1) FR2196492A1 (de)
GB (1) GB1411683A (de)
IT (1) IT990245B (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264072A (en) * 1978-05-26 1981-04-28 Chalmers John E Electronic game apparatus
US4378504A (en) * 1980-03-25 1983-03-29 Omron Tateisi Electronics Co. Proximity switch
EP0613026A1 (de) * 1993-02-25 1994-08-31 Asanuma Corporation Vorrichtung zur Auffindung von Objekten
WO1996023202A1 (en) * 1995-01-27 1996-08-01 The Regents Of The University Of California Micropower material sensor
US6446012B1 (en) 1999-06-23 2002-09-03 Bfcs Technology, Inc. Proximity detector for hard-to-detect materials
US20030067311A1 (en) * 2000-12-06 2003-04-10 Cargol Timothy L. System and method for measuring the dielectric strength of a fluid
US20050130601A1 (en) * 2001-03-16 2005-06-16 Vincent Palermo Methods and apparatus for tuning in an inductive system
US20050258855A1 (en) * 2004-05-19 2005-11-24 Hiroki Kimura Oscillation detecting apparatus and test apparatus

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2131552B (en) * 1982-11-26 1986-12-31 Atomic Energy Authority Uk Non-destructive testing using eddy-currents
CH672383A5 (de) * 1986-10-29 1989-11-15 Baumer Electric Ag
DE10315845B4 (de) * 2003-04-08 2005-10-06 Wolfgang Richter System, Systemkomponenten und Verfahren zur Abwicklung eines hermetisch validierbaren Datentransfers

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3199033A (en) * 1964-08-10 1965-08-03 Tung Sol Electric Inc Condition responsive circuits with plural output of relaxation oscillator balanced
US3200306A (en) * 1963-09-12 1965-08-10 Tung Sol Electric Inc Touch responsive circuit
US3201774A (en) * 1962-12-26 1965-08-17 Tateisi Denki Kabushikikaisha Electrical sensing apparatus
US3255380A (en) * 1961-09-11 1966-06-07 Tung Sol Electric Inc Touch responsive circuit for control of a load
US3324647A (en) * 1964-08-11 1967-06-13 Parmet Company Proximity detector
US3492542A (en) * 1967-02-17 1970-01-27 Wagner Electric Corp Single touch capacity switch

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3255380A (en) * 1961-09-11 1966-06-07 Tung Sol Electric Inc Touch responsive circuit for control of a load
US3201774A (en) * 1962-12-26 1965-08-17 Tateisi Denki Kabushikikaisha Electrical sensing apparatus
US3200306A (en) * 1963-09-12 1965-08-10 Tung Sol Electric Inc Touch responsive circuit
US3199033A (en) * 1964-08-10 1965-08-03 Tung Sol Electric Inc Condition responsive circuits with plural output of relaxation oscillator balanced
US3324647A (en) * 1964-08-11 1967-06-13 Parmet Company Proximity detector
US3492542A (en) * 1967-02-17 1970-01-27 Wagner Electric Corp Single touch capacity switch

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264072A (en) * 1978-05-26 1981-04-28 Chalmers John E Electronic game apparatus
US4378504A (en) * 1980-03-25 1983-03-29 Omron Tateisi Electronics Co. Proximity switch
EP0613026A1 (de) * 1993-02-25 1994-08-31 Asanuma Corporation Vorrichtung zur Auffindung von Objekten
WO1996023202A1 (en) * 1995-01-27 1996-08-01 The Regents Of The University Of California Micropower material sensor
US5832772A (en) * 1995-01-27 1998-11-10 The Regents Of The University Of California Micropower RF material proximity sensor
US6446012B1 (en) 1999-06-23 2002-09-03 Bfcs Technology, Inc. Proximity detector for hard-to-detect materials
US20030067311A1 (en) * 2000-12-06 2003-04-10 Cargol Timothy L. System and method for measuring the dielectric strength of a fluid
US7057393B2 (en) * 2000-12-06 2006-06-06 Massachusetts Institute Of Technology System and method for measuring the dielectric strength of a fluid
US20050130601A1 (en) * 2001-03-16 2005-06-16 Vincent Palermo Methods and apparatus for tuning in an inductive system
US7035608B2 (en) * 2001-03-16 2006-04-25 Aura Communications Technology, Inc. Methods and apparatus for tuning in an inductive system
US20060154615A1 (en) * 2001-03-16 2006-07-13 Vincent Palermo Methods and apparatus for tuning in an inductive system
US7236741B2 (en) 2001-03-16 2007-06-26 Aura Communications Technology, Inc. Methods and apparatus for tuning in an inductive system
US20050258855A1 (en) * 2004-05-19 2005-11-24 Hiroki Kimura Oscillation detecting apparatus and test apparatus
US7034562B2 (en) * 2004-05-19 2006-04-25 Advantest Corporation Oscillation detecting apparatus and test apparatus

Also Published As

Publication number Publication date
DE2341161A1 (de) 1974-02-28
FR2196492A1 (de) 1974-03-15
IT990245B (it) 1975-06-20
GB1411683A (en) 1975-10-29
JPS4959277A (de) 1974-06-08
CA1008145A (en) 1977-04-05

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AS Assignment

Owner name: STUDEBAKER-WORTHINGTON, INC., ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WAGNER ELECTRIC CORPORATION;REEL/FRAME:003984/0757

Effective date: 19801229

AS Assignment

Owner name: COOPER INDUSTRIES, INC., 1001 FANNIN, HOUSTON, TEX

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:EDISON INTERNATIONAL, INC., A CORP. OF DE.;REEL/FRAME:004475/0382

Effective date: 19851031