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Adding Led Help ?

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yusuf

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Hello friends this is water sensor circuit in attachment but here I want to add a Led to indicate whether sensor is in water or not...
Please help ?
Thanks in advance...
 

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I fail to see how this section of the circut can work, as what is Q3 switching a dead short across Q1 and what is Q1 switching as the circuit goes no where.

I think you need to fix this first so we can then see where you can add the led to.

My thoughts is you need to add a second rectifier to supply positive voltage to the circuit other than just through the probes.

Pete.
 

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Last edited:
There is a circuit error. Diodes D1, D2 and D4 will provide more current through the electrodes than taken by the circuit so the current through the electrodes will not be symmetrical AC as you want. To prevent DC through the electrodes put a non-polarized capacitor in series with the electrodes. For that you wouldn't need D2 and D4, just D1.

You can put the LED and its current limiting resistor in series with whatever you have for DC power at the right of the schematic and the collector of Q3. The value of the LED resistor depends upon the DC power voltage and the desired LED current.
 
Dear crutschow please define as you said on drawing circuit diagram because I am new in electronic..
So please make a circuit diagram which you deserve the best ...

thanks in advance...
 
Dear SABorn please give a good circuit diagram which tackles this problem ? I want led to indicate so please help? as crutschow has said so please look crustshow also and help me ?
 
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