EEE 202 midterm 1

A good way to remember Kirchhoff's Voltage Law is:

"What goes up, must come down"

Kirchhoff's Current Law

(KCL): The sum of current entering a node is equal to the sum of current leaving a node, -Or the algebraic sum of all currents entering a node is zero (entering is +, leaving is -)

Kirchhoff's Voltage Law

(KVL): The sum of all the elements and source voltages around a closed path is zero.

If 5A is flowing into a node, and Ix + 3A is flowing out of a node what is the value of Ix?

2A

If the Loop Analysis has 3 unknown variables, how many linear equations are required?

3

If I have two sub-circuits that I created using Superposition and the output current of circuit 1 is 2mA and the output current of circuit 2 is 1mA, what is the output current of my original circuit?

3mA

If the Nodal Analysis has 5 unknown variables, how many linear equations are required?

5

If I have two sub-circuits that I created using Superposition and the output voltage of circuit 1 is 5V and the output voltage of circuit 2 is 3V, what is the output voltage of my original circuit?

8V

Resistors in Series

Current that flows through one must also flow through the other -> the elements are in series.

Series Resistor Networks

Current that flows through one must also flow through the other -> the elements are in series.

A Dependent Voltage Source will always output the same voltage, regardless of the circuit it is connected to.

FALSE

An Independent Current Source will always output the same voltage, regardless of the circuit it is connected to.

FALSE

For circuit analysis, when we replace equivalent resistors for a network of resistors it is because we physically swap the resistors in the lab.

FALSE

Nodal Analysis uses a system of linear equations to solve for the Branch Currents in the circuit.

FALSE

Nodal analysis can only be done if the circuit contains current sources only.

FALSE

SPICE software uses Loop Analysis

FALSE

The resulting circuit using Norton's Theorem will ALWAYS be a voltage supply in series with 2 resistors.

FALSE

Two nodes connected that are not ordinarily connected are called an "Open Circuit"

FALSE

Current Divider Circuits

I1=R2/(R1+R2)

When a resistor is in series with a short circuit, how do we find the total equivalent resistance?

Ignore the short circuit

Multiple Resistor Current Divider

Ii=Isj(Rparallel/Ri) (current division)

Nodal Analysis is a systematic way of applying which circuit analysis technique?

KCL

Loop Analysis is a systematic way of applying which circuit analysis technique?

KVL

In Loop Analysis, what is another name for the Loops?

Mesh

If I do Loop Analysis and find the Current in a branch, how do I find the Voltage?

Ohm's Law

The goal in using Thevenin's Theorem is to reduce a complicated circuit down to:

One voltage supply and a series resistor

To find the Thevenin Resistance, what do I do with Current Supplies?

Open them

What is the correct equation to convert three equal resistors in a Delta configuration into three equal resistors in a Wye configuration?

RY=(1/3)RD

Which equation is correct for the total equivalent resistance of two resistors in series?

Req=R1+R2

Current supplies connected in parallel can be summed together and represented by one equivalent current supply, even if there are resistors between each supply.

TRUE

Resistors are in SERIES when they have the same current flowing through them.

TRUE

Resistors in Parallel with a short, can be neglected.

TRUE

Resistors in parallel with the short circuit can be neglected when determining the Thevenin Resistance.

TRUE

Resistors in series with the open circuit can be neglected when determining the open circuit voltage.

TRUE

Source transformation is a technique where you can substitute an ideal voltage supply in series with any resistor with an ideal current supply in parallel with the same resistor value.

TRUE

Superposition only works for linear circuits.

TRUE

The Norton Equivalent of a circuit is simply the source transformation of the Thevenin Equivalent of the same circuit.

TRUE

The open circuit voltage of a battery and series resistor is equal to the ideal supply voltage

TRUE

The resulting circuit using Thevenin's Theorem will ALWAYS be a voltage supply in series with 2 resistors.

TRUE

The short circuit current of a transistor and parallel resistor is equal to the ideal supply current

TRUE

The unknowns in Nodal Analysis will be mostly Voltages.

TRUE

The voltages of all points on a single node are the same.

TRUE

Ohm's Law

The current through a conductor between two points is directly proportional to the potential difference (voltage) across them and inversely proportional to the resistance between them.

Dependent Source

The magnitude is a function of another voltage or current in the circuit

Parallel Resistor Networks

The resistors share the same (distinct) end nodes (the voltage across them is the same) -> the elements are in parallel

Resistors in Parallel

The resistors share the same (distinct) end nodes (the voltage across them is the same) -> the elements are in parallel: Req=(R1R2)/(R1+R2)

Multiple Source/Resistor Networks

The single loop circuit approach works for any single loop circuits with voltage sources and resistors: (sum of voltage sources)/(sum of resistors)=I

Multiple Source/Resistor Networks

The single node pair circuit approach works for any single node pair circuit with current sources and resistors: = (sum of current sources) <-> (sum of resistors)

When solving circuits with Dependent Sources using KVL, the first step is

To treat the dependent sources just like independent sources

Multiple Resistor Voltage Divider

Vi=V(Ri)/(Rj) (voltage division)

Power Convention Passive sign convention

current should enter the positive voltage terminal

Current Controlled Current Source

dependent source

Current Controlled Voltage Source

dependent source

Voltage Controlled Current Source

dependent source

Voltage Controlled Voltage Source

dependent source

Wye/Delta Network Equations

if R1=R2=R3: RD=3RY if Ra=Rb=Rc: RY=(1/3)RD

Electric power

is the rate at which electric energy is transferred by a circuit

positive power (+)

the element dissipates power

negative power (-)

the element supplies power

Voltage Divider Circuits

v1=R1/R1+R2