Introduction: WATER SENSOR'

Make a simple circuit of a water sensor by using a few electrical devices. Don't trust just try it yourself.
They are-
1) NPN transistor.
2) Switch.
3) Two 500 ohms resistor.
4) A 10kohms resistors.
5) 0.01 capacitor.
6) 0.001 capacitor.
7) A LED ( 1.5 volt).
8) A 3 volt power source.
9) Basic tools



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    Where is the video showing us to make one

    can i ask what is the number of the NPN Transistor cause i can't buy it in the store without the number.

    cant we make the led off totally when the probes arenot immersed into water?

    cant we make the led off totally when the probes arenot immersed into water?

    cant we make the led off totally when the probes are immersed into water?

    also you might want a 470 ohm or a 510 ohm resistor (or two 1k in parallel)

    You're doing something really weird there. The NPN transistor is reverse biased, as drawn And the capacitors are completely redundant.

    You've got a total of 1Kohm limiting current through the LED, this is a bit much for a 3V supply surely?
    NPN transistors should be connected +ve to the collector and -ve to the emitter (you've got it the other way around there) and you don't need a big heat-sunk one for 1 LED.
    Are the low-value capacitors necessary?


    i have got a total of 1kohm resistance limiting the current of led so that it can't light up when the probes are not in water.when you will make it you will see that the led will light up (when the switch is on) a little because of resistors but when you will dip the probes into the water transistor amplification will take place and the led will be brightened.
    no capacitors are just placed there to avoid the loss of electric current. if you will use some higher value capacitors you will need to increase the voltage provided.

    When the probes are not in the water the LED should not light at all, with/without resistors - at 1K it will be dim?
    I stil don't understand the function of the capacitors, even with reference to loss of electric current.