I don't know. What doesn't work? What is it doing?

LED turns on well, but the servo motor doesn't work. The water sensor works fine too!

 

모르겠습니다. 무엇이 작동하지 않나요? 무엇을 하고 있나요?
[/인용하다]

Hi, thank you so much for your help before.
I have two questions about the circuit.
There are many different types of transistors, why did you use that transistor?
Why did you use pnp instead of npn?

 

The 2N3906 is a popular general purpose transistor I use a lot. There are others that would work as well.
PNP because the circuit required high side switching and since the outputs from the LM339 are low it works out.

 

The 2N3906 is a popular general purpose transistor I use a lot. There are others that would work as well.
PNP because the circuit required high side switching and since the outputs from the LM339 are low it works out.

oh, I see ^_^
Is this circuit a cascade system?

 

oh, I see ^_^
Is this circuit a cascade system?

What do you mean by cascade?

 

What do you mean by cascade?

The cascaded system is a circuit that connects amplification stages in series. I learned it at school, and I was wondering if it was the same because the circuit was similar.


I think I asked a weird question. Thank you for your gloomy answer!

 

Not in this case.
Referring to the schematic in post #12, Q1 and Q2 are in series to form an AND gate. Meaning both LED3 and LED4 have to be ON to switch the collector of Q2 to Vcc.

 

Not in this case.
Referring to the schematic in post #12, Q1 and Q2 are in series to form an AND gate. Meaning both LED3 and LED4 have to be ON to switch the collector of Q2 to Vcc.

Thanks!!

 

What sort of actual servo system used for position control does not have position feedback???? Or is the gate controlled by a servo-type motor actuator??? without any position sensing function??
If there is no feedback then it is not a servo system.
If it is a gate operator then it needs to have limit switches to sense the open and closed positions as a means of feedback. Those switches may be operated by a cam someplace in the operating mechanism.