You can also connect different color LED for obtaining the status like connect RED LEDвЂ™s as it is the sign of danger (LED 1 to LED3) which will indicate that that voltage level is less than 40 percentage and need to be taken care. And now by seeing the number of LEDвЂ™s glowing you can easily calculate the status. Connect it to voltage from any battery to be tested at the input which will become power source for the circuit. If above phenomenon is happening your circuit is ready is use. Following table will show the voltage level when different LED will glow вЂ“ Now, increase the input voltage in steps of 1.2V and see LED2 will glow in 2.4V and similarly increase the voltage in steps of 1.2V and LED3 will glow and so on. It will support wide temperature range from 0 degree to +70 degree Celsius.ДЇor calibrating the circuit, apply the power supply and adjusts VR1 so that LED1 just start glowing.

In this we do not require resistor with the LEDвЂ™s because current drive to LEDвЂ™s is regulated and programmed.Д¦. This IC can also work on 3V power supply.ДҐ. You can cascade more ICвЂ™s up to 100 steps.Д¤. This IC can drive LEDвЂ™s, LCD or vacuum fluorescent display.ДЈ. In this user can easily select the dot or bar graph display just by changing a single pin.Дў. LM3914 is a monolithic integrated circuit which senses the analog voltage and derives 10 LEDвЂ™s providing a linear analog display.ДЎ. This simple battery level indicator circuit is based on single IC LM3914 with few more discrete components. 1: Prototype of Battery Level Indicator Circuit on Breadboard Advantage of this circuit is it does not require power supply it will take power supply from the battery of the device itself.ДЇig. So before your battery dies you can recharge it. You can use this battery level indicator circuit with your inverter or with your car battery it will give you indication about your battery status. For example four LED's are glowing means battery capacity is 40 percent.

Battery level indicator will let you know the status of battery of a device just by glowing the number of LED's.

Simple battery monitor circuit