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I am learning how to use Proteus and I have come across the charging and discharging of a capacitor problem. My main problem is on how to use the graph feature of Proteus to simulate how the voltage against time looks like. I have tried to implement this problem on Circuit Wizard and it shows exactly what I want and now I would like to do the same on Proteus but I keep getting a straight line instead. Can someone please guide me through? I have attached the images of my attempt using Proteus and what I expect the graph to look like using Circuit Wizard.

My attempt using Proteus

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Using Circuit Wizard enter image description here

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  • $\begingroup$ Yes. You already have it in your first image. It is a straight line. If it is battery there will be decay. If it is bench top power supply it will be constant / line parallel to the time axis $\endgroup$ – Mahendra Gunawardena Dec 20 '20 at 18:50
  • $\begingroup$ @Mehendra Guanwardena I have changed the source to a pulse source. And now Iam getting the required results. Is there a way of getting coordinates on the graph?, Say coordinates for time at 6.3 Volts? Regards $\endgroup$ – Fil Dec 21 '20 at 15:03
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    $\begingroup$ @Fil Have you looked at the user manual? $\endgroup$ – user8055 Dec 21 '20 at 15:29
  • $\begingroup$ @Mehendra Guanwardena, it is not clear for me. I am only interested in recording the voltage change across the capacitor over time for about 120seconds and then plotting it to display voltage Vs time graph. I'm not sure why it's so difficult to perform this task on Proteus. $\endgroup$ – Fil Dec 22 '20 at 11:14
  • $\begingroup$ @Fil Based on the information provided I think you are already recording the voltage across the capacitor for the first 120 seconds. $\endgroup$ – Mahendra Gunawardena Dec 22 '20 at 13:19
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Try using a replacing a 9V VDC voltage source with a VAC voltage source. Pay attention to the frequency of the VAC voltage source. This should address the issue.

With regard to determining the time value for a particular voltage, review PROTEUS DESIGN SUITE Getting Started Guide. In the section VSM tutorial (Graphs) read around page 230.

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You might have export the raw data and then import to another software like Microsoft Excel to graph the data. This should allow you to review the exact time value for a specific voltage.

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  • $\begingroup$ I had a look at the manual and I can see the graph using VPULSE. However, my task is to use a battery to plot a graph of Voltage across the capacitor Vs time, first for the charging then for the discharging. I though putting a voltmeter across the capacitor or using a voltage probe then running the simulation would produce a set of data for the graph but I am not getting anywhere. Thank you so much for your help through this. $\endgroup$ – Fil Dec 23 '20 at 11:53
  • $\begingroup$ Have you tried to toggle SW1, while connected to the battery. This will simulate the VPULSE. $\endgroup$ – Mahendra Gunawardena Dec 23 '20 at 12:50
  • $\begingroup$ Yes I did this works well with VPULSE. running the simulation for 1 second would produce the required graph. It doesn't run for a dc source and I am still wondering why? $\endgroup$ – Fil Dec 23 '20 at 12:54
  • $\begingroup$ Because DC source is a constant voltage source. Therefore the Capacitor is charged and remains charge with a DC Voltage. So toggling the SW1 on and off you are simulating Alternating Current. By defining VPULSE in the Voltage source an AC (Alternating Current) source characteristics are simulated. I hope this helps. $\endgroup$ – Mahendra Gunawardena Dec 23 '20 at 13:00

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