Capacitive transistorized signaling device
First Claim
1. A switch comprising:
- a capacitive registering element having a conductive surface for purposes of acting as a capacitive element in conjunction with a second body placed in proximity thereto;
a means for generating a signal having sufficiently the slope of a step function to cause the switch to function as a slope differentiation detector with respect to the second body placed in proximity to said capacitive registering element;
means for connecting said conductive surface of said capacitive registering element to said signal generation means so that a change in capacitance between said capacitive registering element and a second body will change the rise time of the slope;
an amplifier connected to said conductive surface and said signal means; and
,an electrical load connected to said amplifier.
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Accused Products
Abstract
An electronic device incorporating a circuit for providing a signal with respect to an on or off mode dependent upon the degree of capacitance. The invention comprises a first and basic embodiment utilizing a signal source having a slope of a step function or specifically one having a fast rise time initiated for example by a clock element. The operative signal criteria demands that the length and slope thereof respectively have an effective amplitude and an effective frequency compatible with the circuit components.
The signal source is fed to a transistor or suitable amplifier having its base connected to a capacitance sensing means. Resistors are provided for appropriate biasing, current limiting and drain functions as well as capacitors for capacitance balancing purposes. The capacitance sensing means can comprise a touch switch which when touched has its capacitance increased causing the device to function. The transistor or amplifier is connected to a load so that when a change of capacitance is sensed, the change will be registered. Other embodiments can incorporate differential amplification means and means to drive the active components with the voltage of the signal source or the clock voltage.
Alternative embodiments of this invention incorporate capacitance sensing means in the form of transducers which can operate in a linear or a sequential mode. The transducers functionally incorporate a change of capacitance by means of moving mechanical elements so that when such change in capacitance is detected by the circuit it will provide an on or off sensing for the circuit or an analog of the change in capacitance. Thus, a reading of the extent of mechanical movement of a mechanically moving object can be transduced into an electrical function or output having substantial linearity.
In summation, the circuit of this invention can be used for a transducer, or a solid state switch.
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Citations
25 Claims
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1. A switch comprising:
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a capacitive registering element having a conductive surface for purposes of acting as a capacitive element in conjunction with a second body placed in proximity thereto; a means for generating a signal having sufficiently the slope of a step function to cause the switch to function as a slope differentiation detector with respect to the second body placed in proximity to said capacitive registering element; means for connecting said conductive surface of said capacitive registering element to said signal generation means so that a change in capacitance between said capacitive registering element and a second body will change the rise time of the slope; an amplifier connected to said conductive surface and said signal means; and
,an electrical load connected to said amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transduction device comprising:
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a capacitive registering element having a first conductor capable of being capacitively coupled to a second body wherein said first conductor is suitably exposed for increases in capacitance with respect to an external body; a differential amplifier connected to said first conductor of said capacitively coupled element; a signal production means producing a signal having a substantially rapid rise or fall time connected to said differential amplifier so that said differential amplifier can differentiate changes in slope caused by changes of capacitance with respect to said capacitance registering element; and
,biasing means for appropriate operation of the differential amplifier. - View Dependent Claims (10, 11, 12, 13)
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14. A capacitive transduction device comprising:
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a capacitive coupler having a first conductive member adapted and placed for capacitive coupling with a body that can move with respect to said first conductive member; a signal source providing a signal having the slope of a step function; and
,an amplifier connected for amplification of a signal developed in response to the change of the slope of the step function between said capacitive coupler and said signal source. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification