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I have been trying to simulate a counter ram, successive-approximate type voltmeter in Proteus. Below I have tried the simulation of it in Proteus. Everything seems right but I don't get the reading output in the display properly. enter image description here

Please let me know what the possible mistake could be. I have give 5V as the DC values to all DC generators. The possible mistakes I could think of was:

  1. The battery is not a sutable input. I tried using a DC generator but that also didn't work.
  2. Maybe the input states 1 and 0 were not appropriate or there was some mistake in the clock.

enter image description here This was the circuit diagram from a textbook on the counter ramp circuit.

Please let me know what could the possible errors be and how to correct it.

edit: I made the following changes after following your suggestions enter image description here

I have used the voltage of 5V to the anode as suggested. The order of LEDs is also reversed. I believe the mistake could be because of the logic states at RO1 and RO2. Could you suggest what changes could be tried there. Also should I use something else for the battery as the input. I flipped the second opamp vertically with - on top. Could that be a possible mistake. let me know how I can improve the project to make it work.

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  • \$\begingroup\$ I don't get the reading output in the display properly is a useless description of what you observe \$\endgroup\$
    – jsotola
    Nov 17, 2020 at 5:16

3 Answers 3

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On the textbook schematic, the A to G pins on the decoder is top to bottom and it is the opposite on your schematic.

The proteus model you used seems to be A to G from top to bottom so you have to connect the right decoder output to the right 7segment pins.

On your schematic, G is connected to A, F to B, etc...

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  • \$\begingroup\$ I did the suggested changes but I was still getting a problem in which the reading output isn't displayed. I was getting a continuous random display of numbers. Could you suggest if I should make some changes to the Digit state of RO1 and RO2. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 5:51
  • \$\begingroup\$ Try to connect pin 3,4,5 of U3 to VCC instead of GND \$\endgroup\$
    – Damien
    Nov 17, 2020 at 6:08
  • \$\begingroup\$ I believe I had connected it to Power. Power is usually used for VCC in Proteus. So how should I proceed. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 6:13
  • \$\begingroup\$ Could you suggest if I should make any changes to the digital state for Ro1 and Ro2. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 6:17
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Your schematic has Digit to COM instead of to +5. It ought to be an open collector active low driver to a Common Anode (CA) digit.

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  • \$\begingroup\$ The COM was the names of the DC generator source but I had given 5 V only. What else should I aim at changing to make the project run successfully. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 6:09
  • \$\begingroup\$ Please suggest to me how to implement Reset given in the diagram to the simulation. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 7:03
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One of the op-amps has V+ on pin 7 and the other one has V+ on pin 4. Only one of them is correct.

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  • \$\begingroup\$ I believe that it was necessary to flip the second Opamp as it was even mentioned in the textbook. Could you suggest if I should make any changes to the digital state for Ro1 and Ro2. \$\endgroup\$
    – Abi Nand
    Nov 17, 2020 at 6:16
  • \$\begingroup\$ Flipping it still does not mean you are allowed to apply power supplies at the wrong polarity. If that was a real chip it would be damaged, maybe emitting smoke. I don't know about Ro1 and Ro2, what does the datasheet of the chip say? \$\endgroup\$
    – Justme
    Nov 17, 2020 at 7:19

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