ELECTRICAL CIRCUITS 1

CHAPTER I
THE CONCEPT OF ELECTRICAL CIRCUITS
Definitions - Definitions
Electrical circuit is a collection of elements or electrical components are interconnected by certain ways and have at least one closed path. Elements or components that will be discussed on Electrical series of courses is limited to elements or components that has two terminals or poles on both ends. For the elements or components that are more than two terminals is discussed on Electronics subjects. Restriction elements or electrical components in electrical circuit or element can be grouped into active and passive components. Active elements are the elements that produce energy in this case is the source of voltage and current sources, regarding this source will be explained in the next chapter. Another element is a passive element in which this element can not produce energy, can be divided into elements which can only absorb energy in this case there is only the component resistor or many also mention the prisoner or barrier with the symbol R, and passive components which can save energy too classified into two components or lemen which absorb energy in the form of a magnetic field in this case the inductor or often also referred to as winding, winding or coil with the symbol L, and passive kompone which absorb energy in the form of a magnetic field in this case is a capacitor or often said with the condenser with the symbol C, the discussion of these three passive components will be discussed in subsequent chapters.
Element or electric kompoen discussed here are:
1. Two-terminal electrical element
a. Source voltage
b. Current source
c. Resistor (R)
d. Inductor (L)
e. Capacitor (C)
2. Electric element is more than two terminals
a. Transistor
b. Op-amp
Speaking of Power series, certainly can not be separated from an understanding of the circuit itself, where the circuit is an interconnection of a set of constituent elements or components coupled with the connecting circuit which are prepared in particular ways and have at least one closed path. In other words with only one closed trajectory that we are able to analyze a circuit. What is meant by a closed path is one path when we start from the point in question would return these ketitik without interruption and did not look at how far or near the path that we travel. Electric circuits are the basis of circuit theory in electrical engineering is the basis of fundamental atay for other sciences such as electronics, power systems, computer systems, engine rpm, and control theory.
Electric current
In the discussion of the electrical circuit, it is important that we know beforehand that some things megenai what is meant by electricity. To understand about electricity, we need to know in advance the understanding of the current. Flow is the change in velocity versus time or load cargo that flows in unit time with the symbol i (from the French word: intensite), in other words the current is moving charge. During the charge as it moves it will appear the flow but when the charge is stationary then the flow would be lost. The charge would move if there is external energy that memepengaruhinya. The charge is the smallest unit of an atomic or sub-section of the atom. Where in the modern atomic theory states atomic nucleus consisting of particles (protons and neutrons are electrically neutral charge) surrounded by electron charge (-), normally electrically neutral atom. The load consists of two types of positive charge and negative charge in the direction of the flow direction of the positive charge (electric current direction) or opposite the direction of electron flow. A particle can be a positive charge if it loses an electron and a negative charge when receiving an electron from another particle. Coulomb is the basic unit of the International System of Units (SI) used to measure electrical charge.
Symbols: Q = load constant
q = charge depending on the unit of time
charge of 1 electron = -1.6021 x 10-19 coulomb
1 coulomb = -6.24 x 1018 electrons
Mathematically flow is defined:
dt
i = dq
Unit: Ampere (A)
In theory the current series is the movement of positive charge. When there is a potential difference disuatu element or component will display a positive current direction dimaan currents flowing from higher potential to lower potential and negative currents flowing the opposite direction.
Various kinds of flows:
1. DC (Direct Current / DC)
DC currents are currents that have a fixed or constant value of the unit of time, meaning that we also review the current diaman at different wakttu will get the same value
2. AC (Alternating Current / AC)
AC current is the current which has a unit value of time-varying characteristics will always be repeated for a certain period of time (have perida time: T).
Stress
Voltage or often people refer to potential differences in the English language voltage is the work done to move a single charge (for one coulomb) on the element or component of a terminal / pole to the terminal / other pole, or on both terminals / poles will have a potential difference if we move / transfer of one coulomb of charge from one terminal to another terminal. The linkage between the work done is actually the energy expended, can be shortened so that the above understanding that stress is the energy per unit charge. Mathematically:
dq
v = dw
Unit: Volt (V)
Then there are the two terms are often used in electrical circuit, namely:
1. Voltage drop / voltage drop
If viewed from a higher potential to lower potential in this regard
from terminal A to terminal B.
2. Voltage rise / voltage rise
If viewed from a lower potential to higher potential in this regard
from terminal B to terminal A.
In this book the term will be used is the sense in item # 1 that is
voltage drop. So if the potential difference between two points is equal to 5
Volt, then the VAB = 5 Volt and VBA = -5 Volts
Energy
The work done by a force of one Newton as far as one meter. So the energy
is something of which we move something out style
for a Newton with the distance or something that moves with
difference in distance of one meter.
In the natural law of Conservation of Energy will apply where the energy actually can not
generated and can not be eliminated, only the energy moves from one form to
the other forms. For example in power stations, energy from moving water
will move into the energy that produces electric energy, electric energy will
move into light energy when it passes through an electric anergy lights,
light energy into heat energy will berpinda if the light bulb
long usage, and so on.
To say whether the energy transmitted or absorbed not only the polarity of the voltage
but also influence the flow direction.
Element / electrical components are classified into:
1. Absorb energy
If a positive current leaving the positive terminal to terminal
elements / components, or a positive flow towards the positive terminal of the elements / components
them.
2. Sending energy
If a positive current into the positive terminal of the terminal elements / components, or
positive current leaving the positive terminal of the element / component.
Energy absorbed / delivered on an element v and the charge voltage
Δq past is Δw = vΔq
Unit: Joule (J)
Power
The average work done
Power mathematically: vi
dt
dq
dq
dw
dq
P = dw = =
Unit: Watt (W)
Analysis series
Finding relations between input and output in the circuit is known,
suppose to find the output voltage / current or determine the energy / power
sent.
There are 2 main branches of the theory of series (input, circuit, output):
1. Circuit analysis (circuit and input to look for output)
2. Circuit synthesis / design (inputs and outputs to look for a series)
Prefix in the SI (System International units)
In the SI to express numbers larger or smaller than one unit
basis, use decimal notation ("standard decimal prefixes") which states
rank of ten.
Abbreviations complete notation means (of units)
atto a 10-18
Femto f 10-15
pico p 10-12
nano n 10-9
micro μ 10-6
milli m 10-3
centi c 10-2
Deci d 10-1
deka da 101
hekto h 102
k kilo 103
mega M 106
giga G 109
tera T 101