Absorved and supplied Power

Thread Starter

michgkou

Joined Oct 3, 2019
30
Hi, trying to find the sources power of the following circuit (using node voltage method), I found that P2A=+9.7818 W (absorved) and the dependent source Pdep. = -0.8263 W (Supplied)

I use a circuit analysis software (LTspice - XVII) to confirm. The analysis showed that P2A= - 9.7818 W and Pdep. = +0.8263 W is that ok? is a different sign contract ?

Here is the circuit:
Καταγραφή.PNG


Thanks
 

WBahn

Joined Mar 31, 2012
24,709
Always, always, ALWAYS ask if the answer makes sense!

You are claiming that one of your two supplies is absorbing about 9.8 W while the other supply is providing about 0.8 W.

So where is the other 9 W that the first supply is absorbing coming from? The resistors?????
 

crutschow

Joined Mar 14, 2008
23,378
Spice defines positive current as going into a node (such as for the positive node of a voltage source), so if you measure the power from the source you will get a negative number for power being delivered by the source (current out of the positive node) and a positive number for power being absorbed by the source.
That explains the difference in sign you observed.
 
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