This simple project is about a 3.7v Lithium Battery Level Indicator, we are going to make a very simple battery level indicator. This indicator circuit is for a 3.7 volts indicator. We have designed this circuit with a few components at home with easily available components. These components can either be collected from an old circuit or can be purchased from an electronics shop easily.
A list of required parts that are needed to build a lithium battery level indicator is given below
First, connect the 1K resistor to the Base and emitter pin of the transistor as shown in the picture given below.
In the second stop solder the 220-ohm resistor to the collector pin of the transistor as shown in the picture.
In this step Connect a 1 kilo-ohm resistor with the second point of the 220-ohm resistor.
In step 4 connect Diode IN4007 with the base point of the Transistor as we have connected in the picture given below. Connect the cathode point of the diode with the base point of the transistor.
Connect – point of green led with Diode – point and +ve point of LED green led with 1k resistor as shown below.
Solder – point of red LED to -ve point of the diode and + point of red LED with collector point of the transistor as we have shown in the diagram given below.
Our circuit has been completed Now we check it by connecting the battery. Connect +ve of 3.7 Volts battery to +ve point of green LED and – point of 3.7V battery to emitter point of the transistor as we have connected in the circuit given below.
When you will connect the 3 V battery the Red LED will glow completely if the battery will be low. Green Led glows when the battery will be charged above 3.2V.
Its tested Circuit and its complete construction points can be seen in the video given below.