Hi, While developing the Python wrapper for Gnucap, I have encountered an issue with the JFET ngspice model.
Here is a netlist containing a JFET component based on the ngspice model: -------------------circuit.ckt-------------------------- *** NJF Test *** .attach jfet.so .model J2N3819 NJF(Beta=1.304m Rd=1 Rs=1 Lambda=2.25m Vto=-3 Is=33.57f + Cgd=1.6p Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1) R3 N528817 N528869 4k I1 N528855 0 DC 6.1m R4 N530614 N528973 50 R2 N528849 N528869 4k V2 N530614 0 SIN 0 1 1e9 0 0 J2 N528817 N529031 N528855 J2N3819 R5 0 N529031 50 J1 N528849 N528973 N528855 J2N3819 V1 N528869 0 18 .END -------------------------------------------------------- Doing a transient analysis on the node N528849 gives the following results, which are similar to those given by Spice: Gnucap> get circuit.ckt Gnucap> print tran v(N528849) Gnucap> tran 0 1n 0.1n #Time v(N528849) 0. 5.8 100.p 6.1586 200.p 6.3693 300.p 6.2136 400.p 5.7429 500.p 5.1405 600.p 4.6337 700.p 4.4201 800.p 4.5832 900.p 5.0749 1.n 5.7175 However, if I add the "uic" option, the initial voltage becomes 0, although there is not any specified initial condition: Gnucap> get circuit.ckt Gnucap> print tran v(N528849) Gnucap> tran 0 1n 0.1n uic #Time v(N528849) 0. 0. 100.p 0.64275 200.p 1.0197 300.p 1.0951 400.p 0.88528 500.p 0.49818 600.p 0.11335 700.p -0.090857 800.p -0.01006 900.p 0.34247 1.n 0.84256 Shouldn't it have given the same results? Can the initial voltage of N528849 be defined to another value than 0? Regards, Xavier _______________________________________________ Gnucap-devel mailing list [email protected] http://lists.gnu.org/mailman/listinfo/gnucap-devel
