DE2341161A1 - CONTROL CIRCUIT RESPONDING TO CHANGES IN CAPACITY AND RESISTANCE - Google Patents

Description

The present invention can advantageously the highly sensitive antenna arrangement for capacitance-sensitive circuits, as shown in FIG the inventor's U.S. Patent 3,760,567, issued June 19, 1973 Carl E. Atkins of the present application.

The present invention relates to control circuits responsive to changes in capacitance and resistance. A large number of such state-responsive circuits are already state of the art, such as e.g. the US patents listed below show:

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3 200 304, 3 200 305, 3 275 897, Re 26 828, 3 314 O8l, 3-339 212, 3 382 4O8, 3 435 298, 3 492 542, 3 551 753, 3 555 368, 3 564 3 ^ 6, 3 568 005, 3 568 006, 3 569 728.

In certain applications, however, such as determining the correct or incorrect application of seat belts in motor vehicles, it is necessary between humans or mammals and. inanimate that To distinguish between objects and loads that occupy seats. The applicant has found that by coupling one a person, mammal or object occupying a seat by means of a feeler attached to a selected one Place or at several selected places of the seat is arranged on an oscillating circuit and by Peststellung the degree of damping of the vibrations in the resonant circuit a sharper distinction between humans and others Mammals and inanimate, conductive or non-conductive objects can be reached if these are in the vicinity or come into contact with a conductive probe located adjacent a selected seating surface. The applicant has also found that this better distinction is based on the various degrees of degradation the quality factor Q of an oscillating circuit is based on humans and other mammals and inanimate objects which are coupled to it.

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The quality factor Q of an oscillating circuit is due to its Energy storage capacity compared to its energy consumption certainly.

When the complex impedance that a human, other mammal, or inanimate object represents, to the Resonant circuit is coupled, the damping of the vibrations in the resonant circuit is increased. Because the complex Impedance of humans and other mammals is an essential ohmic resistance component or one Power consumption-causing component. Includes that at the most inanimate objects is not present, the quality factor Q. of an oscillating circuit is reduced more, when connected to humans or other mammals than when connected to inanimate objects. Due to the reduction in the quality factor Q of the resonant circuit, there is a noticeable reduction in the amplitude and / or the duration of the damped oscillations or the resonance of the oscillating circuit as soon as the oscillating circuit associated with humans or other mammals.

The one that responds to changes in capacitance and resistance Circuit has a wide range of uses and can also be used, for example, to monitor pipe systems

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will. Due to the particularly high sensitivity of the resonant circuit to the load caused by a People, a probe can be used whose area exposed to the object to be measured is only a few square centimeters (a few square inches) is large and is therefore smaller than all previously used feeler surfaces.

According to the present invention, a state or condition-dependent control circuit is provided, in which at least one resonant circuit is periodically excited by pulses emitted by a pulse generator and while each zero potential or level between the pulses can oscillate in its natural or resonance frequency, wherein the change in the amplitude and / or the duration of the oscillations of the resonant circuit caused by connecting with an external impedance with a large capacitive or resistance component is emphasized and / or is detected to generate a control signal. The change in the amplitude of the damped oscillations can occur before their position can be highlighted by an oscillator circuit is provided, which is caused to vibrate abruptly by the positive amplitude of the damped vibrations will. In this way, an oscillating output signal is obtained from the oscillator circuit as soon as the

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positive amplitude of the damped oscillation of the resonant circuit is above a certain threshold and no output signal if the positive amplitude is below the previous ~ correct threshold. The oscillating or non-oscillating output signal can then be determined to form a control signal.

The invention is explained in more detail below with reference to schematic drawings of exemplary embodiments.

It shows:

1 shows a first embodiment of the invention in a schematic circuit diagram capacitive circuit responsive to changes in resistance;

Fig. 2 in a schematic circuit diagram, a second

Embodiment of the circuit according to the invention and

3 shows a third in a schematic circuit diagram

Embodiment of the circuit according to the invention.

As can be seen from Fig. 1, a pulse generator 10 supplies periodic pulses of positive polarity between where the amplitude is essentially at ground potential

409809/0966. ₆ -

These pulses are fed to a bias circuit 12, which has a resistor Rl, a capacitance Cl and a blocking diode Dl comprises. The positive running impulses are passed to an oscillating circuit 14, an inductance Ll, a capacitance C2 and a complex impedance of an outer, not shown Load includes, wherein the external load is connected to the resonant circuit 14 via a sensor 16. A detector 18 is connected to the resonant circuit 14 to detect changes in determine the amplitude and / or the duration of the damped oscillations, which the output of the resonant circuit 14 represent.

The following describes the operation of the Pig. I explained the circuit shown. The pulse generator 10 periodically supplies pulses of positive polarity to the bias circuit 12, these pulses preferably being in the frequency range of 10 to 20 KHz, and the duty cycle being approximately 50 % ; however, other frequencies and other duty cycle values can also be used. The value of the capacitance C1 is chosen so that it approximately represents a short circuit for the positive pulses. During each positive-going pulse, the capacitance Cl is charged with the polarity shown in FIG. 1, but the diode Dl as a whole is biased in such a way that

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it is operated in the forward direction. In this way, a current flows through the inductance Ll of the resonant circuit 14 and thus supplies the inductance Ll with energy which is stored in the magnetic field. the The impedance of the inductance Ll is low and therefore charges the output of the pulse generator 10 to such an extent that that the generation of a control signal in the detector 18 is prevented, and that it is also prevented that the Capacity C2 charges itself to a significant degree. After the stored energy in the inductance Ll has reached a maximum value, the inductance Ll represents a short circuit for the remaining output signal of the Pulse generator represents the amplitude of the pulse for · the remaining part of the positive going pulse to be limited to the earth potential. The energy stored in this way in the inductance Ll does not decrease Oscillation of the oscillating circuit 14 in its natural frequency or Resonance frequency part. When the tail end of the positive going pulse output of the pulse generator 10 reaches is, the magnetic field of the inductance Ll coincides and induces a current pulse that through the inductance Ll to earth, i.e. to earth, flows, and causes the capacitance Cl to a higher Level is charged.

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Since the diode Dl is a stored charge diode, it stores a larger charge for a longer one Time and loses this charge faster than most semiconductor diodes. The diode Dl has a noticeable Diffusion flexibility at the point in time when the trailing edge of the positive pulse traverses and since this conductivity exists, it prevents the diode Dl from removing the bias circuit 12 from the resonant circuit 14 isolated. Since the capacitance Cl of the positive pulse of the pulse generator 10 and the inductive pulse is acted upon by the inductance Ll, it acts like a small battery and causes a flow of current from ground through the inductance Ll, the conductive diode Dl due to diffusion, through the capacitance Cl itself and through the pulse generator 10 to ground. In this way, energy becomes electromagnetic again in the Inductance Ll stored. The reverse current through the diode Dl causes a rapid elimination of the caused by the diffusion extensibility of the conductive state of the diode Dl and the diode Dl is thus enables the bias circuit 12 to be isolated from the resonant circuit 14. Since the diode Dl due the residual charge remaining in the capacitance Cl is biased in the reverse direction, it represents a high impedance for

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represents the resonant circuit 14 and thus prevents its charging. The detector circuit is similar. 18 designed so that it does not charge the resonant circuit 14. If the inductance Ll is no longer supplied with energy, its magnetic field collapses and causes the oscillating circuit 14 to oscillate in its natural frequency or resonance frequency. While the signal between the pulses is at its zero level (0 level), ie in the time between successive positive-going pulses when the amplitude is approximately at ground potential, the capacitance C1 partially discharges through the resistance Rl, The values of the resistors Rl and the capacitance Cl are chosen so that the diode Dl is reverse biased during the zero level between the pulses. The resistor R1 and the capacitance C1 can be replaced by a short circuit if the output of the pulse generator 10 does not assume the ground potential between the positive pulses but instead emits a negative signal.

If no load is coupled to the sensor, the amplitude, the frequency and the duration of the damped oscillations of the resonant circuit lh are relatively fixed and the detector 18 is designed so that it does not respond in this case. However, when a load with a complex

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Impedance, which has a substantial resistance component, is connected to the resonant circuit via the sensor 16, the quality factor Q of the resonant circuit Ik is reduced, as a result of which the amplitude and / or the duration of the oscillations of the resonant circuit 14 are greatly reduced. An inanimate object or an inanimate object, which in most cases has no significant resistance component, has little or no effect on the quality factor Q of the resonant circuit lh and therefore no or only little effect on the amplitude and / or the duration of the Oscillations of the oscillating circuit lh. Furthermore, a load which has a complex impedance with a substantial capacitive component is similarly able to dampen the oscillations of the oscillating circuit 14 when it is connected to the oscillating circuit via the sensor 16.

The detector is preferably designed in a known manner in such a way that it reacts to reductions in amplitude and / or the duration of the damped oscillations that are caused in the resonant circuit, responds to a control signal submit.

The changes in the amplitude and / or the duration of the damped oscillations can advantageously occur

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their feeding to the detector are amplified. The preferred embodiment according to]? Ig. 2 includes an implementation device.

The apparatus shown in Fig. 2 comprises a pulse generator 20, bias circuits 22 and 2 ¹ J of the type shown in Fig. 1, the resonant circuits 26 and 28, amplifying circuits 30 and 32, detecting circuits 34 and 36 and load circuits 38, 40 and 42. The two parallel, a control signal generating circuits by the biasing circuits 22 and 24, the resonant circuits 26 and 28, the gain circuits 30 and 32 and the detector circuits 34 are formed and 36 are in their on ¹ - identical construction and in their function. Therefore, only one of these circuits will be described in detail.

The bias circuit 22 is connected to the pulse generator 20 in order to receive its output pulses and to pass them on to the oscillating circuit 26, which comprises a sensor A1 and an inductance L2, the capacitance for the oscillating circuit from the antenna A1 and the capacitances C7 and C8 of the amplification circuit 30 is formed . The amplification circuit 30 includes a transistor Q feedback capacitances C7 and C8 and bias or

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Current limiting resistors RS and R9 and is with the resonant circuit 26 is connected to receive its output signal and in dependence on this output signal an oscillating input signal for the detector 34 to form.

The detector 3 ^ includes limiting resistors R12 and R13 and transistor Q 5 and is operated to provide a control signal to load circuits 38 and 40 emits as soon as it has a predetermined output signal from the amplification circuit 30 receives. Of the. Circuit according to Fig. 2 works as follows:

The pulse generator 20, the bias circuit 22 and the resonant circuit 26 work as in Pig. I described, the resonant circuit 26 periodically damped oscillations generated with its natural frequency or its resonance frequency. When a complex impedance with a substantial Resistance component is capacitively coupled with the sensor Al, the quality factor Q 'of the oscillating circuit 26 reduced, which in turn reduces the amplitude and / or the duration of the generated vibrations in the resonant circuit 26 each during the 0 level between the pulses of the pulse generator 20 is effected. In addition, a load with a complex impedance that

409809/0968

has an essential capacitive component, similarly being able to »the oscillations of the oscillating circuit 26 to attenuate when it is coupled to the resonant circuit 26 via the antenna A1.

Boost circuit 30 emphasizes the reduction in amplitude of the damped oscillations of resonant circuit 26 caused by the load. In the absence of a positive output from the pulse generator, transistor Q 3 will normally not conduct because there is no forward bias at the base and emitter. The capacitances CJ and C8 are selected according to the requirements of the resonant circuit 26 so that they provide sufficient feedback to force the transistor Q 3 to oscillate when the transistor Q 3 is forward biased. In this way, when a positive pulse is applied to the bias circuit 22 and the resonant circuit 26 to cause the latter to oscillate at its natural frequency as soon as the pulse output of the pulse generator 20 has essentially a ground potential or a negative potential, the Transistor Q 3 suddenly excited to oscillate due to the bias voltage caused by the positive sections of the damped oscillations of the resonant circuit. The vibration

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" ¹⁴ " 23A1161

of transistor Q 3 is maintained during the damped oscillation of the resonant circuit due to the feedback, which reaches through the capacitances C7 and 08 _v · By the resistors R8 and R9 is a Schwellmaß "is determined for the excitation voltage above which the transistor Q 3 resonates . R8 and R9 are selected so that the amplitude of ^: the "normally damped" oscillations - that is, the oscillations not additionally damped by an impedance coupled to the sensor A1 - of the resonant circuit is sufficient to trigger the transistor Q 3 to oscillate. The transistor Q 3 is biased so that a positive DC voltage component is present at its emitter during the oscillations output signal taken from the emitter of transistor Q 3 is a pulsating voltage with a positive DC current component, as long as the resonant circuit 26 oscillates with a sufficient amplitude in its natural frequency, while the emitter output of Q 3 has about the ground potential when the amplitude of the natural frequency oscillations of the oscillating circuit 26 is insufficient to cause oscillations of Q 3 and also only the relative low amplitude of the positive pulse of the pulse generator 20 is present. The amplitude of the natural frequency oscillation of the oscillation circuit is reduced sufficiently to prevent oscillation of the transistor Q 3 when a load is spliced with a

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Impedance, which is a significant capacitive or resistive component has, is capacitively coupled to the sensor Al. This way the diminution will the amplitude of the damped oscillations of the resonant circuit 26 at the emitter output of the transistor Q 3 amplified displayed by taking the output of a periodic oscillating output signal that is a DC component has, changes to a non-oscillating output signal approximately in the range of the ground potential. With the term "Gain" is referred to here as this change in the signal output by transistor Q 3, which occurs when the oscillating circuit is dampened to a certain extent.

The detector 3 ^ _9, which comprises the resistors R12 and R13 and the transistor Q 5, detects the presence or absence of oscillations at the output of the amplification circuit 30 and generates a corresponding control signal. The resistor R12 limits the base current and the resistor R13 limits the collector current of the transistor Q 5. During each period during which the transistor Q 3 oscillates, indicating that the resonant circuit 26 is not loaded, the transistor Q 5 is of the direct current component of the Oscillation made conductive, whereby the collector of the transistor Q 5 is brought approximately to the base potential. When the transistor Q 3 stops

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to oscillate and its emitter is brought approximately to the base potential and thus a load on the resonant circuit 26 indicates, the transistor Q 5 is switched off or locked and its collector rises to the supply voltage, which is preferably about + 10 volts direct current.

In this way, when the sensor Al is coupled to an impedance that is either a substantial one has capacitive or a substantial resistance component, which is the case in humans and other mammals is, a control signal with supply voltage potential at the collector of the transistor Q 5 generated; otherwise, the 'control signal' is essentially on the ^ mass_potential.

The control signals generated in this way can either be used alone or in combination, to control a number of load circuits. For example, the output of detector 34 can be a load circuit or a load circuit 40 or both of these load circuits at the same time. Similarly, the Output of the detector 36 can be used to set up a load circuit 42 or the load circuit 40 or both load circuits 40 and 42 to control. Alternatively, both

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Control signals from detectors 34 and 36 can be used independently or in combination to create a single load circuit 40 to control the logic circuits such as an OR or an AND circuit may include.

In the second preferred embodiment described above, the various circuit components be dimensioned as follows:

Resistances: 1 kiloohm Capacities: 0.22 39 Microfarads •
• Microhenry R2 30 kilo ohms C3 - 390 39 Picofarad Microhenry R3 - 330 ohms C4 0.22 Microfarads R4 330 ohms C5 0.22 Microfarads R5 - 3.3 kilohms C6 - 150 Picofarad R6 - 3.3 kilohms C7 20th Picofarad R7 500 0hm (max) C8 - 150 Picofarad R8 470 ohms C9 20th Picofarad R9 500 0hm (max) ClO RIO - 470 ohms RIl - 470 kilo ohms Inductances: R12 - 33 kilo ohms R13 - 470 kilo ohms L2 R14 - 33 kilo ohms L3 R15 -

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Transistors: 2N4248 Ql - 2N3567 Q2 - 2N5132 Q3 - 2N5132 Q4 - 2N5132 Q5 - 2N5132 Q6 -

Diodes: 1N4148 Dl 1N4148 D2 1N4148 D3 1N4148 OH -

Pig. 3 shows a further embodiment of a detector 44 which comprises a peak value detector or maximum value indicator ¹ sixteenth The output of the maximum value indicator is taken from the junction between the diode D4 and the capacitance C12 and the resistor R1.8. The negative portions of the damped oscillation of the resonant circuit 14 turn off the transistor Q 7 and cause a controlled charge to be supplied to the capacitance C12 via the resistor R17 and the diode D4. The resistance of the resistor R18 is chosen so that a discharge of the capacitance C12 between the positive sections of the damped oscillation of the resonant circuit 14 is prevented. Therefore, when the resonant circuit 14 oscillates at its natural frequency, the diode D4, the capacitance C12 and the resistor R18 operate as a maximum value indicator which keeps the detector output voltage at a potential which is approximately the supply voltage

409809/0066 - ¹ ^

is equivalent to. When the resonant circuit Ik is supplied with energy by the positive pulse of the pulse generator 10, the transistor Q 7 has such a bias that it and its collector are not conductive
has approximately the supply voltage and the output signal
of the detector is in turn held at a potential which corresponds approximately to the supply voltage. If, however, the resonant circuit Ik is coupled to an external impedance by means of the sensor 16, which is either a substantial
has capacitive or resistance components, the
Amplitude of the damped oscillations of the oscillating circuit
14 and thus the time during which the transistor Q 7 is switched off, also reduced.
Because of this, the charge that the capacitance C12
while the resonance oscillations of the oscillating circuit is fed, is reduced, and thus also the peak amplitude, which is determined by the maximum value or peak indicator 46. In this way, a change in the detector output signal of 2: 1 can be used for small changes in amplitude
the damped oscillations of the oscillating circuit Ik can be obtained.

The capacitive and resistance changes responsive circuits described above can be incorporated into different ways can be used. E.g.

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Changes in the antenna load can be caused by a miniaturized load circuit, the one Disc or capacitor plate includes, which for an optional coupling with the sensor Al or the sensor A2 is determined. Such a load circuit can e.g. be built into an object worn by a person, such as a ring or a watch strap and can be used as a key to cause a control circuit to open a lock, for example. The output signal any or all of the detector circuits can be obtained by connecting a polarity reversing circuit be modified. In the case of the detector according to FIG. 3, a negative voltage can be used, by the diode D4 opposite to the direction shown is polarized. Furthermore, the / Jider stands component of the Impedance with which the resonant circuit is loaded can be ohmically coupled to the sensor and not capacitively. It Other detection methods known to the person skilled in the art, i.e. methods for determining changes in the vibrations, can also be used of the resonant circuit are used that differ from the disclosed method; for example, a synchronicity determination or a time comparison method can be used to detect changes in amplitude and / or determine the duration of the damped oscillations. It

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pulse generators other than the one disclosed can also be used to periodically control the resonant circuit to supply with energy and to achieve a natural frequency oscillation of the same.

All information and characteristics disclosed in the registration documents are used, insofar as they are used individually or in combination are new compared to the prior art, claimed as essential to the invention.

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Claims (20)

Ans p.r ü c h e (American fit) 1.) Control circuit characterized by a Pulse generating device (10, 12; 20, 22; 24) the Outputs power supply pulses, and a resonant circuit device (15> 16; 26; 28) which receives the power supply pulses and during the period between The power supply impulses generated oscillations and also indicates when they are having an external impedance a substantial capacitive component or a substantial resistance component is connected by as a result, their oscillations occurring between the power supply pulses are damped. 2. Circuit according to claim 1, characterized. indicates that it comprises a detector device (13; 3 ² J ₉ 36; Hk) which detects the oscillations of the oscillating circuit device (14, 16; 26; 28) occurring between the power supply pulses. 3. Circuit according to claim 1 or 2, characterized in that the detector ^{device (1} IiJ) comprises a peak detector (4-6). 409809/0966 - 23 - _ ox _ 4. Circuit according to one of claims 1 to 3, characterized in that it has a Amplification device (30, 32), which reacts to the oscillations of the oscillating circuit device (18; 34, 36; 44) responds between the power generation pulses, depending on changes in these oscillations To emit output signals. 5 · circuit according to claim 4, characterized in that the reinforcement means (30 or 32) comprises an oscillator circuit (30 or 32) which (26 or 28) means to changes taking place between the power supply pulses oscillations of Resonant 'responds. 6, circuit according to claim 5 »characterized in that that the oscillator circuit (30 or 32) emits an oscillating output voltage which a DC voltage is superimposed when an external impedance with a substantial capacitive component or a substantial resistance component is coupled to the oscillation circuit device (22 or 28). 7. Circuit according to one of claims 1 to 6, characterized in that the 409809/0966 _ ₂₄ _ Detector means (34 or 36) between the power supply pulses generated oscillations of the oscillating circuit device (26 or 28) after the amplification of this Vibrations are monitored by the amplification device (30 or 32) and depending on the tone the same generates a predetermined control signal. 8. Circuit according to one of claims 1 to 7, characterized in that the detector device (34 or 36) a transistor circuit (34 or 36), which depends on the Output signal of the amplification device (30 or 32) between a conductive and a non-conductive state is switched back and forth. 9. Circuit according to one of claims 1 to 8, characterized in that the Pulse generating means comprises a pulse generator (10; 20) which generates power supply pulses which have positive running sections and sections with approximately ground potential, as well as a biasing device (12; 22 or 24) which have a negative signal during the time periods between the power supply pulses seri generated when the power supply voltage is approximately at zero potential. 409809/0966 - 25 - 10. A circuit according to claim 9 _S, characterized in that the biasing device (12; 22 or 24) has a capacitance (Cl, C5 or C6) and a resistor (Rl; R6 or R7) which is connected in parallel to the capacitance, as well as a Blocking diode (Dl; D2 or D3) which is connected in series with the parallel circuit of a resistor and a capacitance includes. 11. Circuit according to one of claims 1 to 10, characterized in that the pulse generating device a pulse generator (10; 20) which outputs a power supply voltage which has alternating positive-running sections and negative-running sections, as well as an insulating device (Dl; D2 or D3), which during each negative part of the power supply voltage die Pulse generator (10, 12; - 20, 22 or 24) electrically from the oscillating circuit device (14, 16; 26 or 28) separates. 12. A circuit according to claim 11, characterized in that the insulating device is a Blocking diode (Dl; D2 or D3) includes. 409809/0966 Circuit according to one of Claims 1 to 12, characterized in that the oscillating circuit device comprises an oscillating circuit (14, 26 or 28) which has a sensor (16; A1 or A2) ₃ via which the external impedance is coupled to the oscillating circuit device will. 14. Circuit, in particular according to one of claims 1 to 13, characterized by a pulse generator (20) which has a power supply voltage generated with a positive-going section, a first signal channel device (22, 26, 30, 3 * J) of the Power supply voltage is supplied and-which the coupling of an external impedance with a substantial capacitive component or a substantial resistance component and depending on the Coupling of such an impedance a predetermined output signal and a second signal channel device (24, 28, 32, 36) which is supplied with the power supply voltage and the coupling of an external impedance with a substantial capacitive component or a determines the essential resistance component and, depending on such a coupling, a predetermined one Output signal generated. 409809/0966 15 · Circuit according to claim 14, characterized indicates that the first and second signal channel means one pretensioning device each (22 or 24) for generating a negative signal between successive positive ones Has sections of the power supply voltage, and an oscillating circuit (26 or 28) to which the output signal of the biasing device (22 or 24) is fed and which comprises a sensor (A1 or A2) for coupling the external impedance, and an amplifying device (30 or 32), the- the output signal of the resonant circuit (26 or 28) receives and amplifies and one Detector device (34 or 36), which points to the output, signal of the amplification device (30 or 32) responds and generates the predetermined control signal. 16. Circuit according to claim 14 or 15, characterized in that it has a first load circuit (38) which is controlled by the first signal channel means (22, 26, 30, 34), and one second load circuit (42) by the second signal channel means (24, 28, 32, 26) is controlled. - 28 - ' 409809/0966 17. Circuit according to one of claims 14 to 16, characterized by a third Load circuit (40), which both from the first signal channel device (22, 26, 30, 34) and from the second Signal channel device (24, 28, 32, 36) is controlled. 18. Circuit according to one of claims 14 to 16, characterized by a load circuit (40) from the first signal channel device (22, 26, 30, 34) as well as from the second signal channel device (24, 28, 32, 36) is controlled. 19. Circuit according to one of claims 1 to 18, characterized in that the pulse generating device. (10, 12; 20, 22 or 24) a pulse generator (10; 20) for generating the power supply voltage, which has alternating negative sections and sections with approximately ground potential, and biasing means (12; 22 or 24) which provide a positive signal during the times between Pulses generated when the power supply voltage is approximately at ground potential. · * ' - 29 - 409809/0966 20. Circuit, in particular according to one of claims 1 to 19 »characterized by a Pulse generator (10; 20), a bias circuit (12; 22 or 24) with a first resistor (Rl; R6 or R7) and a first capacitance (Cl; C5 or C6), which are connected in parallel and in series between the output of the pulse generator (10; 20) and a terminal of a diode with stored charge (Dl; D2 or D3) i.e. a storage diode is connected, an oscillating circuit (14; 26 or 28) with an inductance (Ll; L2 or L3) a second capacitance (C2; C7, C8 or C9, ClO) and a sensor (16; Al or A2), the parallel to each other and to the bias circuit (12; 22 or 24) at the other terminal of the storage diode (Dl; D2 or D3) * um in the period between pulses of the pulse generator (10; 20) to generate vibrations and to the coupling of an external impedance with a substantial capacitive component or a substantial resistance component with the sensor (16; Al or A2) by dampening the vibrations and using a shock-excited oscillator (30 or 32), * Which is connected to the resonant circuit (26, 28) and a detector circuit (18; 34 or 36; 44) for generating a control signal in response to a vorbestimmtejq, output of the oscillator (30 or 32). 409809/0966 Expectations (German form) l.y control circuit arrangement, characterized in that that an oscillating circuit (15, 16, 26, 28) by the pulses of a pulse generator (10, 12; 20, 22; 24) to natural frequency oscillations is excited and that changes in the resonant circuit quality factor, such as those caused by coupling a external impedance with a noticeable capacitive component and / or a noticeable resistance component are caused by means of a measuring device (18; 30,32,34,36; 44) for measuring the amplitude of the natural frequency oscillations are detectable. 2.) Circuit arrangement according to claim 1, characterized in that the measuring device (44) includes a peak value indicator (46) " 3.) Circuit arrangement according to claim 1 or 2, d a through characterized in that it comprises an amplification device (30, 32) which acts on the natural vibrations of the resonant circuit (18; 34, 36; 44) responds between the excitation pulses in order to depend on changes these natural vibrations to emit different output signals. 409809/0966 4.) Circuit arrangement according to claim 3, characterized marked that the measuring device (30, 32, 34, 36) has a transistor circuit (34, 36) comprises, which in dependence on the output signal of the amplifying device (30, 32) between a conductive and a non-conductive state, is switched back and forth ο 5.) Circuit arrangement according to one of claims 1 to 4, characterized in that the pulse generator (10; 20) generates excitation pulses which have positive sections and sections with approximately ground potential, and that a biasing device (12; 22, 24) is provided, which a negative signal during the time periods between the positive Sections of the excitation generated. 6.) Circuit arrangement according to one of claims 3 to 5, characterized in that the biasing device (12; 22, 24) has a capacitance (Cl, C5, C6) and a resistor (Rl; Ή.6, Rl) which is connected in parallel to the capacitance, and a blocking diode (Dl ; D2 D3) which, in series with the parallel connection, comprises a resistor and a capacitance. . -32- 409809/0966 7 ·) Sciialtungsanordnung according to one of claims 1 "to 4, characterized in that the pulse generator (10; 20) emits an excitation voltage, which has alternating positive sections and negative sections, as well as a Trennbzw. Isolation device (Dl; D2, D3) »which during each negative section of the excitation voltage the generator (10, 12; 20, 22 or 24) electrically from the resonant circuit (14, 16; 26 or 28) separates. 8.) Circuit arrangement according to claim 7, characterized in that the separating or insulating device a blocking diode (Dl; D2, D3) comprises. A09809 / 0966 Blank page