smiles
Advanced Member level 4
One circuit creates ultrasound signal through a pipe (to determine whether pipe contains liquid or not, I had liquid in the pipe already), a detector convert that sound to a very small signal (continuous pulse), so it has a amplifying circuit
I draw the circuit here, that pulse acrossed the filter (with dc offset about 1.7Vfrom another source) to the base of Q1.
When I put the probe of the oscilloscope at input location (left of C1), see nothing (because it is very small), but why I see that pulse to the base of Q1 ???
Using oscilloscope I get at the collector of Q1 the same signal (I think it must be pulse with higher amplitude so when pass by C3, DC lost, the amplitude still high enough to activate Q2)
and the result is pulse via C3 lose dc offset and its amplitude is below 0.6V then Q2 doesn't works, so it stop here and microcontroller just only think that the pipe contained no liquid and doesn't allow machine to work.
All components is SMD type, do you know where the wrong is ?
Thanks so much !!!
I draw the circuit here, that pulse acrossed the filter (with dc offset about 1.7Vfrom another source) to the base of Q1.
When I put the probe of the oscilloscope at input location (left of C1), see nothing (because it is very small), but why I see that pulse to the base of Q1 ???
Using oscilloscope I get at the collector of Q1 the same signal (I think it must be pulse with higher amplitude so when pass by C3, DC lost, the amplitude still high enough to activate Q2)
and the result is pulse via C3 lose dc offset and its amplitude is below 0.6V then Q2 doesn't works, so it stop here and microcontroller just only think that the pipe contained no liquid and doesn't allow machine to work.
All components is SMD type, do you know where the wrong is ?
Thanks so much !!!