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How can I improve this circuit ?

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baileychic

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How can I improve this circuit ?

This is the circuit of Automatic Water Level Controller that I have designed. The circuit works fine in Simulation but I want to know how I can change the connection of R13 or I want to know if R13 is connected properly ?

Use winrar 5.x to extract the attached file.
 

Attachments

  • AWLC.rar
    68 KB · Views: 52

You have some relays, switches. Maybe you didn't simulate contact bounce (or chatter, prell), I don't see de-bounce elements, and maybe they are not required. But I can mention this only to be cautious about. I have no idea R13 is connected well or not.
 

Contact bounce is taken care of by SCR as SCR will latch when the Overhead low sensor (magnetic float switch) or Manual On Tact switch is pressed. I am only concerned about R13 connection.
 

I would start by removing Q1,Q2,,Q3,R3,R4,R6,R7,R9 and R10 and re-wiring D3, D4 and D5 to ground, you save nine components and get exactly the same operation.
You will probably have trouble with biasing Q6 to Q9 because they all share the same bias source (R19). It will work if only one float switch operates but may not work if two or more operate simultaneously, you really need a bias resistor in each transistor base and you can increase the values of the resistors to ground to 100K or more quite safely to reduce current consumption.

Brian.
 
@ betwixt

If Q1, Q2 and Q3 circuits are removed then how to show and control manual/auto mode Leds and Overhead tank low Led that is the Leds that you mention. How they are operated ?

Made the changes. In the new circuit what about R9 ? Is that connection okay ?

Edit:

Okay, made the required changes and renumbered the components. So, please consider AWLC-v1.2.rar file for answering further questions.

Is R9 connection okay ?
 

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  • AWLC-v1.1.rar
    66.5 KB · Views: 40
  • AWLC-v1.2.rar
    66.5 KB · Views: 35
Last edited:

I think R9 is OK. I can't use your DSN files, I do not have software to read them but the schematic looks good to me. It is far simpler than before but achieves the same result.

Brian.
 
My .pdsprj (.DSN) file is of Proteus 8.8 SP1 format. That's why I included schematic in PDF format. I wanted a confirmation regarding R9 which you gave now so that I can design the PCB layout and get one PCB manufactured for testing purpose. To keep PCB small I am thinking about using all SMD components except for connectors, relays, SCR, float switches and rotary switch.

Edit:

Okay, here are the final project files with parts renumbered. Will post PCB layout after I design it. If anybody interested can get them manufactured.

Use Winrar 5.x to extract the attached file.
 

Attachments

  • AWLC-v1.4.rar
    72.6 KB · Views: 54

I would be glad your final proteus files including PCB
 

There is a thing I do not understand. Why use a linear supply with a big expensive 50 Hz XFMR when cheap small SMPS modules are selling for less than 10 € ?
 

Still have not drawn the PCB layout. I am bust with some work here. Will soon draw it and post it here.

Current reuirement of the circuit is very less and I can use a 12V transformerless power supply of say 100mA.

230V AC Pri / 12V 250mA Sec 50Hz XFMR costs only 1.5 USD in India.
 

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