pspice output circles connected

why pspice output circles connected

hi all,

when i am doing the pspice simulation, there is a strange thing.
when i use a changeable load to on a current source circuit, it apparently shows a U-I curve with short-circuit current and open-circuit voltage.
but when i set the current source to a sweep of few different input, the output curves connected each other at the begining and the end of each circle, which should be independent at each value of the sweep.

have anyone meet this problem?
ps: picture below

thx!

I think in the 1^st application (changeable load) the current source just serves as a (passive) measurement instrument.
If you make it active (by assigning sweep values), it works as constant current source (CCS). The supply voltage seems to set the limit.

sorry i don't quite understand.
what is the difference between "passive" and "active"?

in the 1st case, my current source just have one specific value.
and in the 2nd case, my current source is set to have a sweep of few values(i.e. 1,2,3,4).
i think each sweep value is supposed to be independent, but i don't know why it's connected.
and when i check the ouput file, it's all okay. but if i select on the figure by Toggle Cursor, there are some points that should not be exist.(i.e. the changeable load is used as a global parameter. so it should not have a 0 point on axis(x,0)(0,y). but the output figures have.)

thx!

MSSOPHIE said:

what is the difference between "passive" and "active"?

Click to expand...

Miss Sophie ;-)

with "passive" I mean you can use a CCS as a current or voltage meter: If you measure/plot the voltage drop between the CCS nodes resp. the current flowing through it, it does not behave as a CCS, i.e. does not deliver a constant current with the given "one specific value", but behaves like a current measuring instrument with zero resistance.

With "active(ly)" assigned sweep values, however, the CCS behaves as it is expected: delivering constant current -- as long as the supply voltage isn't "eaten up" -- the latter behavior seems to be a PSPICE peculiarity which doesn't come with other SPICE flavors.

MSSOPHIE said:

... it should not have a 0 point on axis(x,0)(0,y). but the output figures have.

Click to expand...

Right. The CC-curves look like solar cell characteristics: zero-load voltage depends on radiation energy. The (0,y) 0-points, however, are correct: short-circuit behavior.

erikl said:

Miss Sophie ;-)

Click to expand...

you are right;-)

i checked my data, it's fine.
it might be an error to draw a linear output like this. if it can plot just the data point, it will be fine.
but i didn't find a place to change the output method in my pspice.
maybe i should use the output files to rebuild the curve in the matlab.

thanks!