United States Patent
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`llngraham
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`[19]
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`‘[11]
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`[45]
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`4,731,548
`Patent Number:
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`Date of Patent: Mar. 15, 1988
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`Assignee:
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`[541
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`[75]
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`[73]
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`[211
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`[221
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`[51]
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`[52]
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`[531
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`[5 6]
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`TOUCH CONTROL SWITCH CIRCUIT
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`Inventor:
`Ronald D. Ingraham, Quincy, Mich.
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`Nartron Corporation, Reed City,
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`Mich.
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`Appl. No.: 913,084
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`Filed:
`Sep. 29, 1986
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`link. Cl.‘ ........................................... .. H0lH 35/00
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`U.S. Cl. .................................... 307/116; 307/308;
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`307/632; 200/DIG. 1
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`Field of Search ............... 307/116, 125, 252, 308;
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`315/34, 74, 208, 246, 362; 318/345, 446;
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`323/19, 24; 328/5; 200/DIG. 1
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`References Cited
`U.S. PATENT DOCUMENTS
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`3,549,909 12/1970 Adelson et al.
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`.......... .. 307/252
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`3,641,410 2/1972 Vogelsberg ..
`313/345
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`3/1972 Vogelsberg ..
`3,651,391
`318/446
`5/1972 Bellis ............
`3,666,988
`307/116 X
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`3,899,713
`8/1975 Barkan et al.
`307/308 X
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`3,919,596 11/1975 Bellis ............
`307/308 X
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`3,965,465 6/ 1976 Alexander
`340/274 R
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`3,984,757 10/1976 Gott et
`.. 315/246 X
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`4,016,453 4/ 1977 Moennig
`307/308 X
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`4,031,408
`6/1977
`307/116
`7/1978
`4,101,805
`307/308 X
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`4,119,864 10/1978
`307/116
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`4,152,629
`5/1979
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`.
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`4,159,473
`4,210,322
`4,211,959
`4,213,061
`4,246,533
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`4,264,831
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`4,289,972
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`4,289,980
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`4,308,443
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`4,323,829
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`4,360,737
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`6/1979
`7/1980
`7/1980
`7/1980
`1/1981
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`4/1981
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`9/1981
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`9/1981
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`12/1981
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`4/1982
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`11/1982
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`Senk ......... ..
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`Wem ..........
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`Deavenport et al.
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`Conner
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`Chiang
`Wem ..
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`Wem
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`McLaughlin
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`Tucker et al.
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`Witney et al.
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`Leopold ........... ..
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`............ .. 307/116 X
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`Primary Examiner——Wi1liam M. Shoop, Jr.
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`Assistant Examiner—Sharon D. Logan
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`Attorney, Agent, or Firm—Price, Heneveld, Cooper,
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`DeWitt & Litton
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`ABSTRACT
`[57]
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`in
`A touch controlled electronic switching circuit
`which the body capacitance of the person actuating the
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`device is coupled in series with current limiting resistors
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`and a capacitor with the junction coupled to a logic
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`circuit which responds thereto to provide a direct cur-
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`rent control signal. The logic circuit has an output cou-
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`pled to the gate terminal of a Triac coupled to a load for
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`selectively applying current to said load during both
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`half-cycles of each cycle of the line voltage supplied to
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`the Triac and load.
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`19 Claims, 1 Drawing Figure
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`NEUTRAL
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`Page 1 of 7
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`SAMSUNG EXHIBIT 1008
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`4|.nmPSW
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`Mar. 15, E988
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`._<E._._mz
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`1&3
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`Page 2 of 7
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`TOUCH CONTROL SWITCH CIRCUIT
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`BACKGROUND OF THE INVENTION
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`The present invention relates to an electrical circuit
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`and particularly to a touch controlled electrical switch-
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`ing circuit.
`There exists a variety of electrical switching circuits
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`which respond to a person’s touch on a touch pad
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`which can be in the form of a lamp base or a specific
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`surface area of an electrical appliance to be actuated.
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`Such circuits represent a convenient manner by which a
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`consumer can easily operate appliances without the
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`need for manually actuating a conventional
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`push-button or other type switch. Touch controlled
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`electrical switching circuits have become increasingly
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`popular; for example, in use in controlling table lamps,
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`floor lamps and the like although they have other appli-
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`cations as well. U.S. Pat. Nos. 4,119,864 and 4,360,737
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`are representative of existing touch controlled switch
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`circuits. Typically, such circuits employ the human
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`body as an antenna for picking up 60 Hz radiation exist-
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`ing in an environment by virtue of the line frequency
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`power in the building and utilizes the induced Voltage as
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`a trigger signal for controlling the touch controlled
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`electrical circuit. Such systems, however, can suffer
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`from erratic operation due to variations in the nature of
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`the ambient 60 Hz field and the physiological makeup of
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`30
`the person utilizing the system. Also the prior art sys-
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`tems typically utilize a pulse control for controlling a
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`solid-state switch such as a Triac to be conductive only
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`during a portion of each cycle of operation of the AC
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`power supply thereby reducing the efficiency of such
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`systems.
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`SUMMARY OF THE PRESENT INVENTION
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`The system of the present invention provides an im-
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`proved touch controlled electronic switching circuit in
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`which the body capacitance of the person actuating the
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`device is coupled in a voltage dividing circuit employed
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`to provide a logic output signal for controlling a DC
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`trigger level applied to a Triac or other bilateral solid-
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`state switch coupled between the line voltage source
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`and a load to be controlled. In the preferred embodi-
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`ment of the invention, the body capacitance is coupled
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`in series with current limiting resistors and a second
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`capacitor with the junction coupled to a solid-state
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`switch for providing a control ouput signal to a logic
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`circuit which responds thereto to provide a direct cur-
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`rent control signal. In the preferred embodiment of the
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`invention also, the logic circuit includes a D-flip/tlop
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`circuit having its output coupled to the input gate termi-
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`nal of a Triac for providing a direct current control
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`signal during each half-cycle of each cycle of the line
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`voltage supplied to the Triac and load.
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`Such a circuit provides improved reliability of opera-
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`tion since it does not rely upon induced voltage for its
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`operation. Further, by utilizing a direct current control
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`signal for the solid-state switch, the Triac switch is
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`rendered conductive near the beginning of each half-
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`cycle of operation and remains conductive during each
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`half-cycle of each cycle of operation. Thus, through a
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`DC gate signal,
`inductive loads such as fluorescent
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`lights, motors, etc., may be controlled. These and other
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`objects, features and advantages of the present inven-
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`tion can best be understood by reference to the fo1ow-
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`I
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`4,731,548
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`2
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`ing description thereof together with reference to the
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`accompanying drawing in which:
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`BRIEF DESCRIPTION OF THE DRAWING
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`FIG. l is an electrical circuit diagram in schematic
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`form of the system of the present invention.
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`DETAILED DESCRIPTION OF THE
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`PREFERRED EMBODIMENT
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`In FIG. 1, the electrical circuit 10 for providing a
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`touch controlled electrical switch is shown and includes
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`a touch plate 12 as its control input element which is
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`touched by a person for actuation of the electrical
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`switching circuit. The switching circuit includes a bidi-
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`rectional solid-state switch 20 such as a Triac having
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`one power terminal 21 coupled to the one side of the
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`typically 115 volt 60 Hz AC supply line 30 and its re-
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`maining power terrninal 22 coupled to one terminal 24
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`of a load 26 to be controlled. The remaining terminal 27
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`of the load is coupled to the line neutral conductor 40.
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`A series spike suppression resistor 25 and capacitor 28
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`are coupled across the Triac 20 to prevent false turn-on.
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`The circuit 10 may include a plug which connects
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`directly into, for example, a wall socket to provide .
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`connections for lines 30 and 40 to the building’s wiring
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`system and a socket for receiving terminals 24 and 27 of
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`a load 26 such as a lamp to be controlled. The circuit 10
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`may be built directly into, for example, a base or other
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`mechanical structure associated with a lamp or other
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`appliance and wired directly as shown in FIG. 1 with a
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`plug for plugging directly into a power outlet of the
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`building’s power supply system.
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`The touch plate typically is a conductive element
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`which is insulated from the remaining body or the like
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`of a lamp base or other appliance and is in a location
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`readily accessible by the user. The user’s body includes
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`a capacitance portion represented by capacitor 42 in
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`FIG. 1 which may range in a typical person from be-
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`tween 100.to 300 picofarads. When a person touches
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`touch plate 12, this body capacitance is coupled to a
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`series voltage dividing circuit coupled to the AC supply
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`and including at least one other capacitor 47. The touch
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`plate or terminal 12 is coupled to one terminal of a first
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`resistor 44 serially coupled to a second resistor 46 hav-
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`ing its terminal remote from resistor 44 coupled to the
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`base terminal 52 of a solid-state switch 50 comprising a
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`PNP transistor. Base 52 is also coupled to line supply
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`conductor 30 by a first diode 45 having a cathode cou-
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`pled to the conductor 30 and an anode coupled to base
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`terminal 52. Capacitor 47 is also coupled between base
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`terminal 52 and line 30 and is coupled effectively in
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`series with body capacitor 42 to form a capacitive volt- '
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`age divider including series resistors 44 and 46 between
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`coductor 30 and ground which also corresponds to the
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`ground conductor 40 of the building’s supply line. The
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`emitter terminal 41 of transistor 50 is coupled directly to
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`conductor 30 while the collector terminal 53 is coupled
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`to a capacitor 55 coupled in parallel with resistor 56 and
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`having their terminals remote from collector terminal
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`53 coupled to a negative DC supply conductor 60
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`which is coupled to the neutral or ground conductor 40
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`through a resistor 62 and series coupled rectifier diode
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`64 as shwon in FIG. 1.
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`Transistor 50 is biased in a normally nonconductive
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`state by a resistor 54 coupled between base terminal 52
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`and emitter terminal 51 such that in the absence of body
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`capacitace 42, transistor 50 will be nonconductive and
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`capacitor 55 will be discharged by bleeder resistor 56
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`Page 3 of 7
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`4,731,548
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`5
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`15
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`25
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`30
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`35
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`such that the output signal present at collector terminal
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`53 of transistor 50 will be a logic zero or low level. This
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`input circuit thus will provide a first control output
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`signal which is at a logic low level when plate 12 is not
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`touched and a second level or logic high level when the
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`plate 12 is touched. The touching of plate completes an
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`AC voltage divider between line 30 and 40 including
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`series capacitors 47 and 42 with resistors 44 and 46
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`serially. Thus with the presence of capacitor 42, the AC
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`voltage at the base 52 of transistor 50 during the positive
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`half-cycles of the line voltage will be decreased to for-
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`wardly bias the emitter-to-base junction thereby render-
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`ing transistor '50 conductive. The collector current thus
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`charges capacitor 55 to provide a positive voltage level
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`_ or logic “1” output signal for application to circuit 80.
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`Resistors 44 and 46 should each have a resistance of at
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`least 1 megohms, and in the preferred embodiment of
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`the invention, each have a value of 4.7 megohms which
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`provides isolation between touch plate 12 and suppply
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`20
`line 30 so that no harmful electrical current can be
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`supplied to a person touching plate 12. Two serially
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`coupled resistors are employed in the unlikely event
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`that one resistor could short out, the second resistor
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`continues to provide protection for the user of the cir-
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`cuit. Capacitor 47 was a 0.01 Mfd capacitor in the pre-
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`ferred embodiment. Diode 45 prevents the base-to-ernit-
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`ter junction of transistor from being subjected to re-
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`verse breakover voltages.
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`' A 15 volt DC power supply 70 is included within
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`" circuit 10 for providing power to the logic circuits 80
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`and 90. Supply 70 includes resistor 62 and diode 64 and
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`-'"'a voltage regulator circuit including a 15 volt Zener
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`" diode 72 coupled in parallel with a resistor 74 and ca-
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`pacitor 76. One termninal of this parallel combination is
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`coupled to conductor 30, as shown, while the remaining
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`terminal is coupled to DC supply conductor 60 which.
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`applies a negative 15 volt DC for the logic circuit now
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`‘ described.
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`The logic circuit coupled to transistor 50 and to the
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`1-gate terminal 23 of Triac 20 comprises a two-stage oom-
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`~~ mercially available 4013B integrated circuit having one
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`‘half coupled as a squaring circuit 80 and the second half
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`coupled as a. conventional D-flip/flop circuit 90. The
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`terminal identification numbers on circuits 80 and 90 are
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`45
`the standard commercial identification numbers of the
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`integrated circuit.
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`The squaring circuit 80 responds to positive going 60
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`Hz clock pulses from conductor 40 through current
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`limiting resistor 82 which pulses are applied to the clock
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`input terminal 11 of the circuit. The squaring circuit
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`also receives the control signal from the collector of
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`transistor 50 present across resistor 56 which is applied
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`to input terminal 9 which is the D input of the circuit.
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`Circuit 80 responds to a positive signal on input 11
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`when body capacity 42 is present to provide a positive
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`pulse at the Q output terminal 13. This signal is shown
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`by waveform A in the FIG. and has a pulse width corre-
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`sponding generally to the length of time plate 12 is
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`touched. Pulse A is applied to input terminal 3 of circuit
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`90 which has its SET terminal 6 coupled to conductor
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`60 through resistor 92 and to conductor 30 through
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`capacitor 94 such that when initial power is turned on,
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`this voltage divider holds the SET terminal in a high
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`state assuring that the Q output at terminal 1 remains
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`high and therefore the Triac 20 which is coupled tothe
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`Q output terminal 1 of circuit 90 through resistor 96
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`remains nonconductive when power is initially applied
`to the circuit. The D and Q terminals 5 and 2, respec-
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`50
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`55
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`4
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`tively, of circuit 9 are intercoupled, while terminal 14
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`(Vpp) of circuit 90 is coupled to line 30 as seen in the
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`FIGURE.
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`OPERATION
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`Having described the components and their intercon-
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`nection to form the circuit of the present invention, a
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`description of a cycle of operation is now presented. As
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`noted above, when power is initially applied to the
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`circuit and there is no body capacitance 42 in the cir-
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`cuit, the biasing of the SET terminal of D-flip/flop 90
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`will maintain the Q output high and therefore the Triac
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`20 in the nonconductive state. When touch plate 12 is
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`touched thereby adding capacitance 42, as noted earlier,
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`transistor 50 is rendered conductive during the positive
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`half-cycles of each cycle of the AC supply line voltage,
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`thereby charging capacitor 55 and providing a positive
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`output signal indicated by waveform A in the FIGURE
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`at the Q output 13 of squaring circuit 80. This signal is
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`applied to the clock input terminal 3 of D-flip/flop 90
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`causing the output terminal 1 to switch to the state of
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`terminal 5 which on initial power up was at the low
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`level. Thus, when plate 12 is first touched at a time t1, a
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`negative pulse indicated by waveform B in the FIG-
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`URE will be applied to the Triac 20 rendering it con-
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`ductive and illuminating lamp 26 or applying power to
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`whatever appliance is coupled to terminals 24 and 27.
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`When the user removes contact with touch plate 12,
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`transistor 50 is nonconductive and capacitor 55 dis-
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`charges through resistor 56; however, the D-flip/flop
`90 is latched and output 1 remains at a direct current
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`low level and the Triac 20 remains conductive during
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`each half-cycle of each cycle of the applied line fre-
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`quency voltage. The next time, however, touch plate 12
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`is touched, generating a second positive pulse on input
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`terminal 9 of squaring circuit 80, a second positive pulse
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`also indicated by waveform A is applied to terminal 3 of
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`circuit 90. The flip/flop circuit 90 responds to change
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`states and provide a positive going edge to waveform B
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`indicated at time t2 in the Figure, thereby turning the
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`Triac 20 off and extinguishing lamp 26. Thus, alternate
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`touches of plate 12 will cause flip/flop 90 to change
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`states for providing the control pulse to the Triac 20.
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`Waveform B provides a continuous DC signal as op-
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`posed to alternate half-cycle pulses thereby rendering
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`the Triac conductive during the entire cycle of line
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`frequency voltage applied between conductors 30 and
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`40 which efficiently provides power to lamp 26. A
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`suitable adjustable time delay and reset circuit can be
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`coupled between the squaring circuit 80 and triac 20 to
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`provide an adjustable duty cycle of power to load 26.
`The circuit of the present invention therefore pro-
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`vides a relatively inexpensive and efficient circuit in
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`which operation is improved by providing an AC volt-
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`age dividing network including the body capacitance as
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`a controlled element and a DC control signal for the
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`gate of a bidirectional switch such as a Triac. The sys-
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`tem utilizes a minimum of components with safety fea-
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`tures for protecting the user. It will become apparent to
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`those skilled in the art that various modifications to the
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`preferred embodiment of the invention can be made
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`without departing from the spirit or scope thereof as
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`defined by the appended claims.
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`The embodiments of the invention in which an exclu-
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`sive property or privilege is claimed are defined as
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`follows:
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`1. A touch controlled electric switching circuit com-
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`prising:
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`Page 4 of 7
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`4,731,548
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`5
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`15
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`5
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`a source of power for the actuation of a load to be
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`selectively coupled to said source of power;
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`a controllable means for selectively coupling said
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`source to a load; and
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`a control circuit including a series voltage divider
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`input circuit including at least one capacitor having
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`a first terminal connected to said source of power
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`and an input touch terminal for coupling a person’s
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`body capacitance in series with said at least one
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`‘ capacitor such that the voltage across said one
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`capacitor produced by said source of power is
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`changed when said input touch terminal is touched
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`and said control circuit provides a control output
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`signal in response to the touching of said touch
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`terminal which signal is applied to said controllable
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`means for selectively coupling said source of
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`power to said load.
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`2. The circuit as defined in claim 1 wherein said
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`source of power is an alternating current source and
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`wherein said controllable means comprises a first solid-
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`state switch.
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`3. The circuit as defined in claim 2 wherein said input
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`circuit is coupled to said source of power and includes
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`resistance means coupled in series between said touch
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`terminal and said at least one capacitor.
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`4. The circuit as defined in claim 3 wherein said resis-
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`tance means comprises a pair of serially coupled resis-
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`tors each having a resistance of at least 1 megaohm.
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`5. A touch controlled electric switching circuit com-
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`_
`prising:
`a source of power for the actuation of a load to be
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`selectively coupled to said source of power;
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`a controllable means for selectively coupling said
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`source to a load; and
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`a control circuit including a series voltage divider
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`input circuit including at least one capacitor and an
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`input touch terminal for coupling a person’s body
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`capacitance in series with said at least one capaci-
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`tor such that the voltage between said one capaci-
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`tor and said touch terminal
`is reduced when
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`touched and said control circuit provides a control
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`output signal in response to the touching of said
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`touch terminal which signal is applied to said con-
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`trollable means for selectively coupling said source-
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`of power to said load, wherein said source of
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`power is an alternating current source and wherein
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`said controllable means comprises a first solid-state
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`switch, wherein said input circuit is coupled to said
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`source of power and includes resistance means
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`coupled in series between said touch terminal and
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`said at least one capacitor, wherein said resistance
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`means comprises a pair of serially coupled resistors
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`each having a resistance of at least 1 megaohm and,
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`wherein the junction of said at least one capacitor
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`and said resistance means is coupled to a control
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`terminal of a second solid-state switch coupled to
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`said power source and responsive to the change in
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`capacitance and resulting voltage change at said
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`junction to provide a controlling signal.
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`6. The circuit as defined in claim 5 wherein said con-
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`trol circuit further includes a logic circuit having an
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`input terminal coupled to said second solid-state switch
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`and output terminal coupled to said first solid-state
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`switch, said logic circuit latching in response to succes-
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`sive controlling signals for providing said control out-
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`put signal.
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`45
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`6
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`7. The circuit as defined in claim 6 wherein said logic
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`circuit comprises a squaring circuit serially coupled to a
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`D-flip/flop circuit.
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`8. A touch controlled electric switching circuit com-
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`prising:
`a source of alternating current power for the actua-
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`tion of a load to be selectively coupled to said
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`source;
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`a first solid-state switch for selectively coupling a
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`load to said source and having a control input ter-
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`minal for receiving control signals; and
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`a control circuit including a touch plate responsive to
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`the touch of an individual to provide a direct cur-
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`rent control output signal applied to said control
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`input terminal such that said first switch is ren-
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`dered conductive during each half-cycle of each
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`cycle of applied alternating current voltage,
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`wherein said control circuit includes a series volt-
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`age divider input circuit including said touch plate
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`and at least one capacitor having a terminal remote
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`from said touch plate connected to said source of
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`alternating current power for coupling a person’s
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`body capacitance in series with said at least one
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`capacitor and said source of alternating current
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`power such that said control circuit responds to the
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`change in voltage across said one capacitor to se-
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`lectively provide said direct current control signal.
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`9. The circuit as defined in claim 8 wherein said input
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`circuit is coupled to said source of power and includes
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`resistance means coupled in series between said touch
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`plate and said at least one capacitor.
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`10. The circuit as defined in claim 9 wherein said
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`resistance means comprises a pair of serially coupled
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`resistors each having a resistance of at least 1 megohm.
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`11. A touch controlled electronic switching circuit
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`comprising:
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`a source of alternating current power for the actua-
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`tion of a load to be selectively coupled to said
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`source;
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`a first solid-state switch for selectively coupling a
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`load to said source and having a control input ter-
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`minal for receiving control signals; and
`
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`a control circuit including a touch plate responsive to
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`the touch of an individual to provide a direct cur-
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`rent control output signal applied to said control
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`input terminal such that said first switch is ren-
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`dered conductive during each half-cycle of each
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`cycle of applied alternating current voltage,
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`wherein said control circuit includes a series volt-
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`age divider input circuit including at least one ca-
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`pacitor and said touch plate is coupled to said at
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`least one capacitor for coupling a person’s body
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`capacitance in series with said at least one capaci-
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`tor such that said control circuit selectively pro-
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`vides said direct current control signal, said source
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`of power and includes resistance means coupled in
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`series between said touch plate and said at least one
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`capacitor, wherein said resistance means comprises
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`a pair of serially coupled resistors each having a
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`resistance of at least 1 megaohm and, wherein the
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`junction of said at least one capacitor and said
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`resistance means is coupled to a control terminal of
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`a second solid-state switch coupled to said power
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`source and responsive to the change in capacitance
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`and resulting voltage change at said junction to
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`provide a controlling signal.
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`12. The circuit as defined in claim 11 wherein said
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`control circuit further includes a logic circuit having an
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`Page 5 of 7
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`7
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`input terminal coupled to said second solid-state switch
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`and ouput
`terminal coupled to said first solid-state
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`switch, said logic circuit latching in response to succes-
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`sive controlling signals for providing said control out-
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`put signal.
`13. The circuit as defined in claim 12 wherein said
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`logic circuit comprises a squaring circuit serially cou-
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`pled to a D-flip/flop circuit.
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`14. A touch controlled electrical switching circuit for
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`controlling power applied to a load, said circuit com-
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`prising:
`a solid-state switch and means for coupling said
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`switch between a load to be controlled and a sup-
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`ply of electrical power, said switch having a con-
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`trol input-terminal; and
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`a control circuit including an input circuit and a logic
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`circuit for receiving tactile command information
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`from an operator and for providing a control out-
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`put signal applied to said control input terminal of
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`20
`said solid-state switch, wherein said input circuit
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`includes a touch terminal coupled to at least one
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`capacitor having a terminal remote from said touch
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`terminal coupled to the supply of’ power to define a
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`voltage divider circuit with a person’s body capaci-
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`tance, said input circuit further including resistance
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`means coupled in series with said touch terminal
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`and said capacitor for limiting current to said touch
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`terminal and voltage level responsive means re-
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`sponsive to said voltage divider circuit for causing
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`said logic circuit to change the state of said control
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`. output signal.
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`15. A touch controlled electrical switching circuit for
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`controlling power applied to a load, said circuit com-
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`prising:
`a solid-state switch and means for coupling said
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`switch between a load to be controlled and a supply of
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`4,731,548
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`8
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`electrical power, said switch having a control input
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`terminal; and
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`a control circuit including an input circuit and a logic
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`circuit for receiving tactile command information
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`from an operator and for providing a control out-
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`put signal applied to said control input terminal of
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`said solid-state switch, wherein said input circuit
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`includes a touch terminal coupled to at least one
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`capacitor having a terminal remote from said touch
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`terminal coupled to the supply of power to define a
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`voltage divid