## Power and Energy Conservation

A circuit with two sources and three two port elements is studied. Some voltages and currents are given. Voltage of the voltage source is unknown. We need to analyze the circuit, find power of other elements and use the energy conservation to determine the power of the voltage source.

## Circuit Containing Only Sources

We go through solving a circuit which only containes independent sources: two voltage sources and two current sources. KVL and KCL are used to determine voltages and currents.

## Problem 1-15: Power of Independent Sources

Determining power of independent voltage and current sources. Passive sign and active sign conventions are used to find out which source is supplyingpower and which one is absorbing.

## Problem 1-14: Current of A Voltage Source

Two simple circuits are used to demonstrate the characteristic of voltage and current sources. In both cases, the voltage sources are in series with current sources.

## Problem 1-13: Voltage of A Current Source

Five circuits are considered to explain the characteristics of voltage and current sources. It is shown how voltage sources enforce their voltages on parallel elements.

## Problem 1-4: Elements, Nodes, Loops and Branches

Finding the number of elements, nodes, loops and branches of a circuit

## Problem 1-2: Power and Conductance of Resistors

Finding power and conductance of resistors from the current and resistance

## Problem 1-1: Power of Elements

Finding the power of elements and determining which one is supplying power and which one is absorbing it.