How do I simulate the above circuit in LTSPICE? The way I have it set up right now gives me a singular matrix error which I don't understand. Vi is a AC signal with a frequency of 100kHz and a small amplitude of less than 10mV.

Circuit image

SPICE ciruit


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    \$\begingroup\$ Consider showing the error and code so people can maybe see what the issue is. What they won't do is build the model for you from the question you copied... \$\endgroup\$
    – Solar Mike
    Mar 8, 2018 at 8:18
  • \$\begingroup\$ You're right. I'll revise it. \$\endgroup\$
    – Sackhugger
    Mar 8, 2018 at 8:19
  • \$\begingroup\$ gommer's answer is the one you're looking for, but also consider you may need a DC path for the output reading. For example, a 1g resistor in parallel with the 10n capacitor. \$\endgroup\$ Mar 9, 2018 at 7:06

1 Answer 1


Obviously, B1 has no return path. That arrow on top is ground but it's a different node than the ground you use on the bottom of the schematic.

Change the arrow type ground on top (COM) to the closed triangle type ground (node 0) and you'll be OK.


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