Hello everyone,
I need help regarding a DIY project of capacitive sensor for constant level monitoring of Liquid. As I am complete novice in this field I have searched in YouTube and found a circuit which I have attached,now when I am simulating this circuit in Circuit Wizard somehow it is not working,now I am clueless why it is not working(output led is not blinking).ill post the video link also.

If anyone could help me to understand the circuit it would be really helpful .

 

the first part of the circuit is an oscillator, it is quite possible that it doesn't oscillate if the capacitor is shorted. e.g. if the sensor is shorted. it'd need to be an insulator of some sort and the sensor apparently needs to work as a capacitor.

 

Hi Tri,
Post the Circuit Wizard circuit.
E

 

One problem with using a relaxation oscillator in this circuit, is that it only needs 300k of leakage resistance across the sensor to stop it working (and you don't need to spill much water in it to get 300k of leakage resistance)

The remainder of the circuit is a frequency-to-voltage converter, with an under-frequency alarm.
Have a look at this datasheet
https://www.ti.com/lit/ds/symlink/lm2907-n.pdf?ts=1653735920386
which is an IC that does the same thing.

 

Hi Tri,
Post the Circuit Wizard circuit.
E