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.

Date of Patent:
Aug. 30, 1977

Filed:

Feb. 04, 1976
Applicant:
Inventors:

Kenji Yashiro, Tokyo, JA;

Yoshifumi Saeki, Tokyo, JA;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R / ;
U.S. Cl.
CPC ...
324133 ; 307351 ; 3241 / ; 3241 / ;
Abstract

The operative status of an electrical apparatus unit such as a television receiver, incorporating an AC-DC converter, and drawing a substantial amount of current is sensed while differentiating from the usage of a lower amount of current, as when operating in a standby mode. The sensor distinguishes between the standby current waveform and a distinctly different current waveform generated when the AC-DC converter draws current in the mode in which full power is on. The sensor incorporates a reference current detector responsive to the mean of the absolute value of alternating current flowing through a power line to the electrical unit, and a peak value current detector responsive to the peak value of the periodic signal on the power line. A comparator circuit receives outputs from both detectors, and provides an output signal when the ratio therebetween is in excess of a predetermined value, this condition only applying when the AC-DC converter is operative. The comparator may comprise a differential amplifier which periodically triggers a pulse generator to maintain a selected signal level and activate a relay as long as the selected proportionality exists between the peak and mean values of the AC power signal.


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