Car Battery Charge Indicator with 10 LED by LM3914

Description: 

This circuit is designed for visual inspection of the car battaries.  The minimum and maximum operating values of the circuit are 3V and 25V. The circuit can be used with any other circuits as a voltage indicator.

The charge of the battery can be easily seen by the 10 LED sequence. The circuit can be used in a measure range of 3V-25V in other circuits after adjusted. But it can not show voltage values less than 3V and the IC wil be demaged if it is used with values grater than 25V. LM3914 is a dot/bar display driver and it includes 10 voltage comperator inside. The voltage difference between each comperator is equal. The minimum input voltage value can be adjusted by using P2. For this adjustment process, D10 LED will illimunate at the minimum voltage. By using the P1 and P2, the minimum and maximum voltage values can be set. This interval is devided in to ten parts inside the LM3914 IC.

JP1 determines the mode of the display. Two operating modes are available; dot and bar display modes. 

You can use LM3914's datasheet for more detailed information about usage. Download

Parts List:

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