BEEE MIDTERMS

Module 3 +

Network

An interconnection of elements or devices

Circuit

A network providing one or more closed paths

Branch

A network topology element representing a single element such as a voltage source or a resistor. Represents any two-terminal element.

Node

The point of connection between two or more branches. It is usually indicated by a dot in a circuit

TRUE

TRUE OR FALSE: If a short circuit (a connecting wire) connects two nodes, the two nodes constitute a single node.

Loop

It is an any closed path in a circuit. It is formed by starting at a node, passing through a set of nodes, and returning to the starting node without passing through any node more than once.

If it contains a branch which is not in any other loop.

When is a loop considered independent?

chain-connected or connected sequentially, end to end.

Elements are in series when they are ____?

connected to the same pair of terminals

Elements are in parallel when they are ___?

Kirchoff’s Current and Voltage Law

These laws describe the relation of values of currents that flow through a junction point and the voltages in an electrical circuit loop. They describe how electrical current flows in all of the billions of electric appliances and devices, as well as throughout homes and businesses, that are in use continually on Earth.

German Physicist Gustav Kirchoff (1845)

Who is the proponent behind Kirchoff’s Law

Mesh

It is a loop which does not contain any other loops within it.

Super Mesh

It results when two meshes have a (dependent or independent) current source in common.

Maxwell’s Mesh Analysis

This method involves a set of independent loop or mesh currents assigned to as many meshes as exists in the circuit.

Planar Circuit

A circuit that can be drawn on a flat surface without any wires crossing each other.

Non-planar Circuit

A circuit that cannot be drawn on a flat surface without any wires crossing each other.

Sinusoid

A signal that has the form of the sine or cosine function

Alternating Current

aka sinusoidal current, this current reverses at regular time intervals and has alternately positive and negative values

AC Waveform

It is a disturbance, cannot be seen, and can be constructed from sine waves

1. Sinusoidal wave

2. Half wave

3. Triangular wave

4. Semi-circular wave

5. Trapezoidal wave

6. Square wave

What are the six types of waveform?

Cycle

one complete series of values, equivalent to one revolution

2pi*f

What is the equivalent value of angular velocity (w)

Time Period

The time taken in seconds for an alternating quantity to complete one cycle.

T = 2pi/w

What is time period T equal to?

Frequency

The number of cycles completed per second; also the reciprocal of time period.

60 Hz

What is the standard frequency of the electricity supply in the PH?

Peak Value/Maximum Value/Crest Value/Amplitude

The largest value reached in a half cycle (during positive or negative) of the waveform. They are represented by Vm or Im

Average or Mean Value

This is the average value measured over a half cycle (since over a complete cycle the average value is zero). Mathematically, it is the area under the curve divided by the base.

Effective Value

This is the current which will produce the same heating effect as an equivalent direct current. It is sometimes called as root mean square (rms) value and whenever an alternatiing quantity is given, it is assumed to be the rms value.

RMS value over average value

Formula for form factor

maximum value over RMS value

Formula for peak factor

1.11

What is the form factor for sine waves?

1.41

What is the peak factor for sine waves?

Instantaneous Values

The values of the alternating quantities at any instant of time or angle of rotation (represented by a small letter)

In-phase

What do you call the phase when the angle is 0?

sin(wt + 90)

cos(wt) = ?

cos(wt - 90)

sin(wt) = ?

Leading waveform

One waveform that is ahead of another

Lagging waveform

One waveform that is behind of another