Low battery voltage indicator circuit for a metal detector
Patent 4488115 Issued on December 11, 1984. Estimated Expiration Date: 
September 30, 2002. 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.
September 30, 2002. 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 2820959 3196357 3882481 3896371 3909722 3919642 Induction balance metal detector with inverse discrimination Wide pulse gated metal detector with improved noise rejection Metal detector circuit having momentary disabled output Power source voltage checking device particularly for checking the voltage of a battery in a camera Patent #: 4376265 InventorAssigneeApplicationNo. 06/429489 filed on 09/30/1982US Classes:324/329, Using movable transmitter and receiver324/133, Nonquantitative (e.g., hot-line indicator, polarity tester)324/436, Including oscillator in measurement circuit340/636.1, Battery340/636.15By voltageExaminersPrimary: Strecker, Gerard R.Attorney, Agent or FirmInternational ClassG01V 3/10 (20060101)AbstractA metal detector is disclosed which has a transmit coil, a receive coil, and circuit means for detecting metal objects due to a change in the magnetic coupling between the coils. Circuit board arrangement techniques are disclosed which enable the close placement of the transmit and receive coils and the circuit board, thereby allowing packaging of the metal detector in a small package. A low battery voltage indicator circuit is provided to warble an audio indicator signal to indicate sufficient battery voltage. In the event the battery voltage drops below a certain level, the warbling of the indicator signal ceases and a steady tone is generated thereby indicating a low battery voltage condition. | |
