Phasors simplify this analysis by considering only the amplitude and phase components of the sine wave. An example could be the sum of voltages across a series connection of a resistor and an inductor. So the difference is that power is the rate of change of energy.Īnswer: Addition of two out-of-phase sinusoidal signals is rather complicated in the time domain. In the context of electric circuits, energy (w) is related to power by the following relationship p = vi =dw/dt

What id difference between power and energy?Īnswer: Energy is defined as the capacity of a physical system to perform work. For controlled sources the control laws are used to get the necessary extra equations.1. In case of an independent voltage source the extra equation necessary to solve for the unknown current is obtained by equating the difference of the relevant terminal voltages with the output voltage of the generator. In modified node equation technique the voltage sources and all the controlled sources are replaced by unknown current sources. To combat these difficulties we can modify both the node equation technique and the loop equation technique that will be capable of handling circuits containing any type of linear electrical sources. Moreover source transformation cannot be used for ideal sources. On the other hand circuit theorems cannot be explained unless the students are conversant with the circuit analysis techniques. However, this concept being related to Thevenin and Norton’s theorems it becomes difficult to teach source transformation unless these theorems are known to the students. In order to accommodate both types of generators, source transformation is recommended. The node equation technique, for example, is suitable for circuits containing current sources and the loop equation technique is suitable for circuits containing voltage sources. For this purpose two different techniques viz., node equation technique and loop equation technique are used that are derived from Kirchoff’s current law and Kirchhoff’s voltage law respectively. The subject mainly deals with the analysis of linear electrical circuit containing linear passive elements, independent linear voltage and current sources and linear controlled sources.

Circuit Theory is a very important subject included in the first year curriculum for both electrical and electronic engineering.

Circuit theory questions and answers