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Why there is a difference in sign of current ?

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rahulprem2013

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Hi

I simulated the below circuit in Pspice. But the green current marker is showing +1.4 mA (voltage drop across diode is 0.6 V)and the other color current marker is showing -1.4 mA . Why there is a sign difference in current in a single wire ? And more over the current shouldn't be negative value from a diode right ? Wheres the problem ?

diode.JPG

and
How to get a Ideal Diode in Pspice ?

Thank You
Rahul
 

The markers don't show wire current - they show the current in a device pin - hence the difference in the sign.

Keith
 

Rahul, rotate R2 by 180 deg and the sign will change.
 

LvW said:
Rahul, rotate R2 by 180 deg and the sign will change.
Click to expand...

HI
I tried rotating the resistor by 180 deg, even after that the markers are showing same value
How to get ideal diode with zero voltage drop in pspice ?
 

I don't use Pspice but in my simulator, current probes show the current at the pin. If you put a current probe at the opposite end of the resistor the sign will change. Positive indicates current going into the pin, negative means the current is out of the pin.

Keith

- - - Updated - - -

From the Pspice manual:
I[ac](< device >) Current into a device
Click to expand...

Keith
 

rahulprem2013 said:
Hi

I simulated the below circuit in Pspice. But the green current marker is showing +1.4 mA (voltage drop across diode is 0.6 V)and the other color current marker is showing -1.4 mA . Why there is a sign difference in current in a single wire ? And more over the current shouldn't be negative value from a diode right ? Wheres the problem ?
Click to expand...
the 'sign' of a current tells you in which direction it is flowing. there's no problem.
when you probe for a current, the probe 'assumes' a particular current direction. If the actual current is in the opposite direction it is marked as negative.

How to get a Ideal Diode in Pspice ?
Click to expand...

why would you want such a device ? the whole idea of spice, and other good simulation packages is to model the real world. Not some fantansy world.
 

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