The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 18, 1976
Filed:
Sep. 27, 1973
Robert E Green, Santa Ana, CA (US);
Other;
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.