Low battery voltage indicator for a portable digital electronic instrument
Patent 4010456 Issued on March 1, 1977. Estimated Expiration Date: 
March 1, 1994. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 1, 1994. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3526887 3755806 3864677 3882481 3898790 InventorApplicationNo. 556753 filed on 03/10/1975US Classes:340/636.15, By voltage340/661, Comparison340/691.6, Information display345/46Light-emitting diodesExaminersPrimary: Curtis, Marshall M.Attorney, Agent or FirmAbstractThe output voltage of a battery in a portable digital electronic instrument is compared with an internal voltage reference. When the battery voltage falls below the reference voltage, the true decimal point of the number being displayed is not illuminated and a plurality of the adjacent decimal points are illuminated. | |
