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:
Aug. 16, 1977
Filed:
Jun. 23, 1975
William Webb, Jr, Denver, CO (US);
Unitec, Inc., Denver, CO (US);
Abstract
An electrical quantity measuring device is disclosed that includes a probe unit presenting high impedance, which device is suitable for measuring voltage. The components of the measuring device, except for the probe unit, are housed in a cabinet having a meter mounted thereon for external viewing. The probe unit has a contactor and provides an output signal indicative of the predetermined quantity of an element to be measured during contact of the element with the contactor and a ground lead. A high impedance between the contactor and the probe output is provided by a plurality of field effect transistors, and an operational amplifier, the gate of the first of which transistors is connected with the contactor and the gate of the second of which receives a feedback signal from the processing circuitry of the measuring device within the cabinet. A third field effect transistor is connected with the first field effect transistor and compensates for leakage current. The processing circuitry of the measuring device includes a pair of series connected transistors with the junction at the output side of the transistors providing an output signal suitable for scope usage and also providing the feedback signal to the high impedance section of the probe unit. The output from the processing circuitry is also coupled through range selection switching circuitry and driving circuitry to a meter as well as to indicating circuitry for indicating the polarity of a reading on the meter.