# How do I get a graph that shows the current in a circuit with a capacitor?

Discussion in 'Electronics Resources' started by Plecto, Dec 9, 2010.

1. ### Plecto Thread Starter New Member

Dec 9, 2010
3
0
Hi. It's now just a week untill my math exam. I want to be able to set up circuits in multisim consisting simply of a voltage source, resistor, a capacitator and maybe an inductor and then see how the voltage over the different components aswell as the current through the circuit developes after t=0 just to see if I have gotten the math right. How do I sort of "stop time" in multisim and see the development bit by bit?

2. ### Dave Retired Moderator

Nov 17, 2003
6,960
144

Requires Java.

If there are specifics you want help with feel free to ask questions and I'm sure someone will be able to point you in the right direction before your exam.

Dave

3. ### Plecto Thread Starter New Member

Dec 9, 2010
3
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Thanks for the reply. The tool seemed to work just fine. With a constant powersource the numbers seemed to be very correct. I did however come across some problems when trying to use a sine-wave. I hooked up an AC power supply (12sin(20t)) in series with a resistor (4 Ohm) and a capacitator (0.01F). The thing is that it shows a peak voltage of 3.63V which is clearly wrong, the peak voltage is supposed to be around 10V. I then set the "DC offset" in the AC settings to 12V aswell. The peak voltage then became correct at close to 10V, but it shows this after only 27ms which is aswell clearly wrong. The peak shoudnt come untill around 220ms. What's wrong here? And what is "DC offset"?

4. ### Plecto Thread Starter New Member

Dec 9, 2010
3
0
Anyone? I've got all these numbers that I need for my exam, but I have no idea whether or not they are correct I've tried several setups with both capacitators and inductors but nothing will give the correct output. In a circuit with a AC power (sin(1000t)), resistor (4Ohm) and an inductor (0,004H), it told me that the voltage over the inductor was over 1V and that the current in the circuit was over 60mA, which is over twice the actual case.

5. ### SgtWookie Expert

Jul 17, 2007
22,182
1,728
It would help a great deal if you would post the original schematic, problem, and the expected result.