hi friends
i'm trying to build a water tank controller using 89c51 ....to prevent salt formation on probes i m generrating a 2000hz frequency from uC and transmitting it to the water tank .for detection of water level m using a small circuit comprising of 1 m ohm resistor , capacitor(0.1 uF) and bc548 ...but the circuit is highly sensitive...even a small touch of a finger or something on the probe is detected by the circuit....please suggest me how i can improve the working and efficiency of the circuit .... attached below is the circuit diagram i made....
thanks,
With Best regards,
Amit