water level indicator with


Posted on Feb 7, 2014

When the water is empty the wires in the tank are open circuited and the 180K resistors pulls the switch low hence opening the switch and LEDs are OFF. As the water starts filling up, first the wire in the tank connected to S1 and the + supply are shorted by water. This closes the switch S1 and turns the LED1 ON.


water level indicator with
Click here to download the full size of the above Circuit.

As the water continues to fill the tank, the LEDs2, 3 and 4 light up gradually. When the water is full, the base of the transistor BC148 is pulled high by the water and this saturates the transistor, turning the buzzer ON. The SPST switch has to be opened to turn the buzzer OFF.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Simple DC to 20 MHz Driver
    Astable multivibrator circuits
    Mains Frequency Monitor circuit and explanation
    Mentality of designing of electric fan of infrared remote-control command
    transformer Single pole AC to DC conversion circuit
    Headphone amplifier with TDA2004 circuit
    IC rprecision waveform generator with sweep and frequency modulation
    Practical differentiator



    Top