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Hello everyone! My circuit seems to be working correctly, both on Circuit Lab and on the vero board. But I can't seem to understand the warning that circuitlab is posting every time I run the DC solver for the DC operating point analysis. The voltages that are being output in circuitlab are fine.

My circuit -

Is it something to be worried about? If there is any trouble with the circuit, then I want to rectify it. So, I was wondering if I could know as to what might be causing this warning.

Thanks. :)

Hi banerjen,

Thanks for sharing the circuit. You have a pretty complicated circuit here, and we will have to look into why its giving you the warning.

For now though, I changed a few things around that have gotten rid of the warning. First I removed the capacitor in parallel with V1 (it's an ideal voltage source anyway). I also got rid of the digital not in front of the voltage source and instead replaced it with two 5V square waves. Now on the transient simulation, you can see what happens to the P1-P2 when your inputs A and B are changing.

Dear Humberto,

Thank you very much. :) I was wondering as to if you could integrate a Motor component with CircuitLab as it would look neater and we could use it instead of using a resistor and an inductor all the time and also if you could program the back-emf part (although I don't know how difficult it must be). :)

I am also curious as to what the "non-linear convergence" error in the DC analysis means. I would be very glad if you could just give me some insight on it or maybe guide me to a link from where I could read up on it. I would love to know more.

Thank you very much.

Best regards,

Nandan.

When both FETs are turned off , the diodes are open circuits which leaves the motor hanging at an indeterminate voltage. It might be enough to just hang one resistor from one side of the motor to ground to make sure the motor always has some definitive voltage.

In general, you want the circuit to have all nodes hooked up to something, under all conditions. In the real world those nodes will float at some indeterminate value-- in the simulator they can flot to really wild values and mess up the simulation.

It would be nice to have a switch in the simulator that hangs a 10Megohm resistor onto each node.

And to simulate stray capacity, another switch than hangs 22pf on each node.