AC convergence solutions

Do not use steps 3-5 of the DC convergence solutions. Using these steps may not produce a valid DC operating point, which is essential for SPICE to linearize the circuit. See the AC analysis description. Once DC convergence is achieved, the AC analysis will also converge. 

Convergence failures are not always a function of SPICE and therefore cannot always be fixed using. OPTIONS statements or other convergence techniques. Convergence failures may result from hardware problems. 

Kielkowski, Ron. 1995. Inside SPICE. New York McGraw-Hill. 

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