Re: gEDA-user: Why the current is negative(of ngspice)?

[al davis <ad151@xxxxxxxxxxxxxxxx>]

> 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.

I rarely want to know node voltages, except as a way to 
calculate what I really want.  Why not let the simulator tell 
you what you really want?


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