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12V Battery LED Level Indicator circuit

12V Battery LED Level Indicator circuit
In the circuit diagram LEDs D1 toD10 displays the extent of the battery in either dot or bargraph mode. Resistor R4 connected between pins 6, 7 and ground controls the brightness of the LEDs. Resistors R1 and POT R2 forms a voltage divider network and the POT R2 will be used for calibration.

The circuit shown here is intended in order to observe between 10.5V to 15V DC. The calibration of the circuit will be done as follows. when setting up the circuit connect a 12V DC supply to the input. currently regulate the 10K POT to induce the LED10 glow (in dot mode) or LEDs up to 10 glow (in bar mode). currently decrease the voltage in steps and at 10.5 volts only LED1 can glow. Switch S1 will be used to pick out between dot mode and bar graph mode. When S1 is closed, pin9 of the IC gets connected to the positive supply and bar graph mode gets enabled. When switch S1 is open pin9 of the IC gets disconnected to the positive supply and the display goes to the dot mode.

With very little modification the circuit will be used to observe different voltage ranges. For this simply take away the resistor R3 and connect the higher level voltage to the input. now change the POT R2 till} LED 10 glows (in dot mode). take away the higher voltage level and connect the lower level to the input. now connect a high valuePOT (say 500K) in theplace of R3 and change it till LED1 alone glows. now take away the POT, live the current resistance across it and connect a resistor of identical value in the place of R3. the extent monitor is prepared.