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Here is my schematic

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New Member
Here is the schematic i am going to use....

I want to use it to make a VERY sensitive water level indicator......

Any suggestions on the circuit ? I want it to trigger the LED at the very slightest contact of the waters surface with the point of the needle... so can I make it any more sensitive ?????

Thanks for your help guys !!!



New Member
Your chat & data posts give the transistor as a BC548B.
The Radio Shack number or a 2N2222A should be it's equal.
I'm not familiar with the BC5488B, maybe a typo?
Have you tried this circuit yet?
Could the 1.2 K ohm resistor be a typo also?
It probably won't work with that little resistance.
More like 120 k ohm. [or 47k as pebe says]
I would replace the 1.2 K ohm with a 500 K pot.
When you get the sensitivity you need remove the pot,
measure the resistance and replace it with a comparable resistor.
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