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Battery checker

  • US 3,974,441 A
  • Filed: 06/25/1975
  • Issued: 08/10/1976
  • Est. Priority Date: 06/25/1975
  • Status: Expired due to Term
First Claim
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1. A device for checking the energy level of a battery comprising manually operated switching means, a series connected light emitting diode and a silicon controlled rectifier placed across said battery terminals by said switching means, circuit means for applying a predetermined increment of the battery voltage to the control gate of said rectifier, a series connected first diode and a further light emitting diode also placed across said battery terminals by said switching means, and a second diode connected between the junction of said first mentioned diode with said further light emitting diode and the junction of said first mentioned light emitting diode with said silicon controlled rectifier, whereby if said predetermined increment of battery voltage is of sufficient magnitude said silicon controlled rectifier will go to the on condition forwarding biasing said first mentioned light emitting diode, the current flow through said first and second diodes maintaining the voltage across said further light emitting diode below the forwardly biasing level, and if said predetermined voltage increment is insufficient to produce the on condition in said silicon controlled rectifier said further light emitting diode will be forwardly biased, with the voltage drop across said further light emitting diode providing a reverse bias on said second diode to thus provide a go, no-go visual indication at said light emitting diodes of the voltage level of the battery.

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