Basic Circuit Elements

Prof J R Lucas
An electrical circuit is an interconnection of electrical circuit elements. These circuit
elements can be categorized into two types, namely active elements and passive elements.
Some Definitions/explanations of ele
Network Theorems  Alternating Current examples  J. R. Lucas
In the previous chapter, we have been dealing mainly with direct current resistive circuits in
order to the principles of the various theorems clear. As was mentioned, these theories are
equall
Alternating Current Theory  J R Lucas
An alternating waveform is a periodic waveform which alternate between positive and
negative values. Unlike direct waveforms, they cannot be characterised by one magnitude as
their amplitude is continuously varying f
BSc Engineering Degree Course, Level 2
EE201 Theory of Electricity Professor J R Lucas
Problems on Circuit Transients
Introduction
Switching of a circuit from one state to another, either by a change in the source condition or
by a change in the circuit c
Electrical Safety
Protection
All electrical circuits and devices require protection against fault conditions, providing safety to
personnel and preventing the device from severe damage. There are several forms of protection, each
of which has its merits a
Electromagnetic Theory 
J. R. Lucas
One of the basic theorems in electromagnetism is the Amperes Law which relates, the
magnetic field produced by an electric current, to the current passing through a conductor.
magnetic
Amperes Law
current
field
Amperes
Three Phase Theory  Professor J R Lucas
As you are aware, to transmit power with single phase alternating current, we need two
wires (live wire and neutral). However you would have seen that distribution lines
usually have only 4 wires. This is because d
Analysis of NonSinusoidal Waveforms
Waveforms
Up to the present, we have been considering direct waveforms and sinusoidal alternating
waveforms as shown in figure 1(a) and 1(b) respectively.
a(t)
a(t)
a(t) = Am sin(t+)
a(t) = A
t
t
Figure 1(a) direct wav
Resonance & Mutual Inductance
Resonance
You are probably familiar with Resonance in sound. In this we know that at resonance we
here the greatest sound (water column) and have the maximum vibration (string). The same
idea is present in electrical engineer
Analysis of NonSinusoidal Waveforms Part 2 Laplace Transform
In the earlier section, we learnt that the Fourier Series may be written in complex form as
f (t ) = C n e jn ot
n =
where the Fourier coefficient Cn is given by
1 t o +T
jn t
Cn =
f (t ) e
Matrix Analysis of Networks
It is tedious to analyse large network using normal equations. It is easier and more convenient
to formulate large networks in matrix form.
To have a neat form of solution, it is necessary to know the structure of a network and
Network Theorems 
J. R. Lucas
The fundamental laws that govern electric circuits are the Ohms Law and the Kirchoffs
Laws.
Ohms Law
Ohms Law states that the voltage v(t) across a resistor R is directly proportional to the
current i(t) flowing through it.