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Alarm circuit for residual capacity of battery in portable radio transmitting and receiving apparatus

  • US 5,936,534 A
  • Filed: 06/17/1998
  • Issued: 08/10/1999
  • Est. Priority Date: 06/17/1997
  • Status: Expired due to Term
First Claim
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1. An alarm circuit for the residual capacity of a battery in a portable radio transmitting and receiving apparatus, comprising:

  • a memory for storing an alarm voltage of said battery, and a sound alarm generated through either a speaker or a receiver;

    means for detecting a voltage of said battery to generate a detected voltage;

    means for comparing said detected voltage with said alarm voltage to generate an alarm signal, when said detected voltage is lower than said alarm voltage to drive said speaker when said apparatus is in a waiting state and to drive said receiver when said apparatus is in a speaking state; and

    means for controlling one of said speaker and receiver to be driven in accordance with said sound alarm selected when said alarm signal is generated.

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