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:
Feb. 16, 1988
Filed:
Feb. 04, 1987
Allan E Marble, Halifax, CA;
Leslie T Russell, Halifax, CA;
Other;
Abstract
The circuit comprises an elapsed time indicating meter and a silicon-controlled rectifier, used to supply power to the meter, connected in series across the circuit's first and third terminals. Additionally, the circuit includes a small resistor connected between the second and third input terminals, that is, connected in series with the a.c. device. This small resistor receives the current through the a.c. device and the voltage across the small resistor is indicative of the operational state of the a.c. device. A variable potentiometer is connected full scale across the small resistor and the variable voltage is amplified by a common-base transistor. This amplified voltage is both rectified and filtered, serving as the SCR's gate terminal input for triggering the SCR. The potentiometer is adjustable to allow the SCR to trigger in either one of two conditions. The potentiometer can be adjusted so that the SCR triggers at all times during which the motor is turned on, or the potentiometer can be adjusted so that the SCR turns on only when the device, such as a motor, is operated under load. The latter condition allows the elapsed time indicating meter to record the cumulative time during which the device is actually performing work.