WATER LEVEL INDICATOR ALARM

This simple transistor based water level indicator circuit is very useful to indicate the water levels in a tank. Whenever tank gets filled, we get alerts on particular levels. The main components required for this project are,

• BC547 Transistor
  
• LEDs
  
• Resistors(Value is specified in the circuit )
• Buzzer
  
• Battery(9V)
  
• Breadboard or PCB
  

CIRCUIT DIAGRAM

               Here we are using transistor as a Switch. Initially there is no voltage applied to the base of the Transistor Q1 and the transistor is in OFF state and no current is flowing through collector and emitter and LED is OFF.

               When the water level reaches to Point A in the tank, the positive side of the battery gets connected to the base of the Transistor Q1 through the water. So when a positive voltage has been applied to the base of the Transistor Q1, it gets into ON state and current starts flowing from collector to emitter. And RED LED glows. 

                Here the resistors R4,R5,R6 are used to drop down the base voltage to 0.7 V.