al davis wrote: >> Yang Hawk wrote: >>> and How could I check current between any two nodes? > > On Saturday 17 May 2008, Dan McMahill wrote: >> I'm assuming you mean "how could I check current in any >> branch". You can insert a zero volt DC voltage source in any >> branch and monitor the current through it. > > In gnucap, just ask for the current .. > > .probe tran i(d1) ij(d1) ic(d1) ic(q1) ie(q1) ice(q1) > > or whatever ... > > i(d1) = total current (ij + ic) > ij(d1) = junction current > ic(d1) = current in the diode's capacitance > > ic(q1) = current flowing into the collector > ie(q1) = current flowing into the emitter. (probably negative) > ice(q1) = current that flows into the collector through the > transistor and out of the emitter > > There are lots more! > > Putting zero volt sources every place I want to measure current > is a royal pain.
not only is it a royal pain, as far as I know you can't get the break out of currents in junctions with spice like Al's gnucap example here. In other words, I think if you want to monitor the junction current vs the current charging a diodes capacitance in spice you have to do incredibly ugly things like monitor the voltage across it and have it drive another diode that has a model with C set to zero and similar hacks. Not at all straightforward. In gnucap, as Al points out, it is simple. This has implications for understanding noise in high frequency bipolar oscillators. -Dan _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
