Use LM 3914 Integrated circuit to make an LED meter as Volt meter or Audio level indicator. Only a few discrete components are required to construct a Bar graph display in addition to this IC. LM 3914 / 3915 / 3916 version ICs are used in display circuits to drive either individual LED or Matrix LED. These are mainly used in circuits where precision output display is needed. Its each output becomes low one by one with the increment of 125 milli volts in its input. Let us see the details of its design.
With this circuit, you can assess the voltage level in Lead Acid Car battery or Inverter battery. It gives LED indications in Dot Mode display to show the level of voltage in the battery. A Lead Acid battery attains 13.8 volts and tubular battery 14.8 volts in the fully charged state. If the battery voltage level drops below 10 volts, it needs immediate charging, and if it is not attaining full charge, it cannot be used to drive the load.
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