ELECTRONIC CONTROL DEVICE WITH CONDITION RESPONSIVE OSCILLATOR

• US 3,723,901 A
• Filed: 02/03/1971
• Issued: 03/27/1973
• Est. Priority Date: 02/03/1970
• Status: Expired due to Term

• Current Assignee: Jean Pierre Nicolas
• Original Assignee: Jean Pierre Nicolas
• Inventors: Nicolas, Jean Pierre
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Grimm, Siegfried H.
• Application Number:
  US05/112,171
• Time in Patent Office: 783 Days
• Field of Search: 331/65,117R 307/116,125,308 317/146 328/5 340/258C,279
• US Class Current: 331/65
• CPC Class Codes: H03K 17/945 Proximity switches H03K17/96 takes precedence
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

An electronic device intended to supply an electric control signal in response to the momentary application of an impedance which may be constituted by the impedance of the human body between an input terminal and earth. The device comprising a single active amplifier element in a feedback oscillator in which the feedback circuit is completed, for example, by being touched. The active member is biased in class C so that it is virtually blocked until oscillations set in by closing the feedback circuit with the human body whereupon the active element passes into class A condition. The control signal is formed by the average current of the active member resulting from amplification of the detected oscillations on the input electrode of the active element. This single amplifier stage produces simultaneously a feedback of the high frequency current, a detection of the peaks of this high frequency current and an amplification in direct current of the detected current, the state of oscillation continuing or not, according to a chosen mode of operation after the said impedence is no longer applied.

Claims

1. An electronic device intended to supply an electric control signal, in particular a signal of sufficient amplitude for controlling a relay, in response to the momentary application of an impedance which may be constituted by the impedance of the human body, between an input terminal for starting and earth, said device comprising a single active amplifier element, connected as a feedback oscillator having an open feedback circuit ending at the said input terminal for starting, the active element being biased in claSs C so that it is virtually blocked in the absence of oscillations when the feedback circuit is open, the application of the said impedance between the starting terminal and earth closing the feedback circuit such that the oscillator begins to oscillate and causes the active element to pass into a state of conduction, substantially into class A, the control signal being formed by the average current supplied by the active element, obtained by amplification of the component of direct current due to the detection of the oscillations on the input electrode of the active element, this single amplifier stage producing simultaneously a feedback of the high frequency current, a detection of the peaks of this high frequency current and an amplification in direct current of the detected current, this state of oscillation continuing or not, according to a chosen mode of operation after the said impedance is no longer applied.

2. A device according to claim 1 wherein the chosen mode of operation is such that the state of oscillation is maintained after the impedance is no longer applied, and wherein means is provided for short-circuiting the feedback to earth so as to stop the oscillations and return the active element to the blocked state.

3. A device according to claim 2, wherein the means for short-circuiting the feedback to earth comprise a second input terminal for stopping, connected to the feedback circuit such that the application of the said impedance between the stopping terminal and earth short-circuits the feedback to earth and, by stopping the oscillations, returns the active element to the blocked state.

4. A device according to claim 1, wherein the active element is a transistor, and the oscillator is of the tuned-base type, comprising an oscillatory circuit connected between the starting terminal and the base of the said transistor, and wherein a coil coupled to the said oscillatory circuit is connected in series in the collector circuit of the said transistor.

5. A device according to claim 1, comprising means for controlling the degree of feedback of the feedback circuit.

6. A device according to claim 4, including means for controlling the degree of feedback of the feedback circuit, said controlling means being means which varies the coupling of the oscillatory circuit and of the coil coupled to the said oscillatory circuit.

7. A device according to claim 6, in which the coupling between the coil of the oscillatory circuit and the coupled coil is realized by a variometer, the said variometer providing for a translation of one of the coils relative to the other.

8. A device according to claim 7, wherein the said variometer comprises an outer casing defining a square section and provided internally with a shoulder capable of immobilizing one of the coils, the two coils being wound on forms of a non-conducting material, one of which is provided with a central aperture and the other with a thread, so that the coil having a central aperture is the immobile coil, a plastic screw provided with a head passing through the said aperture of the immobile coil in order to engage in the thread of the other coil.

9. A device according to claim 4, including means for adjusting the degree of feedback of the feedback circuit, said controlling means being a variable resistance provided with the oscillatory circuit in order to modify its resistance.

10. A device according to claim 9 wherein said variable resistance is connected in parallel with said oscillatory circuit.

11. A device according to claim 9 wherein said variable resistance is connected in series between said oscillatory circuit and the input of the active amplifier element.