Problem 1-15: Power of Independent Sources

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Basic Concepts, Electrical Circuits, Electrical Circuits Problems

Determine the power of each source.
a)
Voltage and Current Sources
b)

Solution
a) The current source keeps the current of the loop $2A$ and the voltage source keeps the voltage across the current source $3v$ as shown below.

Voltage and Current Sources

For the voltage source the current enters from the positive terminal. Therefore, the passive sign convention should be used to find the sign of power:
$P=V \times I= 3 \times 2 =6W > 0$ absorbing power
For the current source, the current leaves from the positive terminal. Hence, the active sign convention should be used:
$P= - V \times I= - 3 \times 2 =-6W < 0$ supplying power

b) Similarily, the voltage across the current source and the currentpassing through thevoltage source can be easily determined by voltage and current sources, respectively:

For this problem, the current enters to the voltage source from the negative terminal. Thus, the active sign convention should be used:

$P=-V \times I= -3 \times 2 =-6W 0$ absorbing power

active sign convention Current Source Independent Sources passive sign convention Power Voltage Source

Comments

8 responses to “Problem 1-15: Power of Independent Sources”

March 20, 2011

thirulok

sir,
whats the main difference of absorbing power and supplying power??
mainly here, the circuits consists of 2 SOURCE….. which one is absorb the power from other???

Reply
1. March 22, 2011
  
  Dr. Yaz Z. Li
  
  Would you please clarify your question? In circuit a, the voltage source is absorbing current from the current source. In b, the current source is absorbing power from the voltage source.
  
  Reply
  1. November 30, 2014
    
    Hashem
    
    I think at the last line of the solution there is a mistake, you should complete the solving
    
    Reply
    1. December 14, 2014
      
      Yaz
      
      What is the mistake?
      
      Reply
2. September 19, 2015
  
  salahuddin
  
  if i m not wrong . Example, Absorbing power = when u connect source to battery, & supplying power = when u charge battery,
  
  Reply
June 19, 2011

Dhruv

i am totally confused when there is a voltage source and a current source in a circuit

Reply
1. May 29, 2012
  
  Mohamed
  
  Me too
  
  Reply
September 27, 2013

Mesh Analysis – Supermesh | Solved Problems

[…] used to find the sign of power: P_{V_S}=-V_S times I_1=-49.2 W < 0 (supplying power). Take a look here if you are would like to know how power of independent sources should be […]

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