4. DC Circuits
▰ The closed path in which
the direct current flows is
called the DC circuit. The
current flows in only one
direction and it is mostly
used in low voltage
applications. The resistor
is the main component of
the DC circuit. 4
6. SERIES DC CIRCUITS
▰ The circuit in which have DC
series source, and the
number of resistors are
connected end to end so
that same current flow
through them is called a DC
series circuit.
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7. PARALLEL DC CIRCUITS
▰ The circuit which have DC
source and one end of all the
resistors is joined to a
common point and other end
are also joined to another
common point so that
current flows through them
is called a DC parallel circuit.
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8. SERIES-PARALLEL DC CIRCUITS
▰ The circuit in which
series and parallel
circuit are connected in
series is called a series
parallel circuit.
8
10. AC Circuits
▰ The current that changes its magnitude and
polarity at regular intervals of time is called an
alternating current. The major advantage of
using the alternating current instead of direct
current is that the alternating current is easily
transformed from higher voltage level to lower
voltage level.
10
13. DIFFERENCE OF DC AND AC CIRCUITS
13
Basis Alternating current Direct current
Definition The direction of the current reverse
periodically.
The direction of the
current remain same.
Causes of flow of
electrons
Rotating a coil in a uniform magnetic
field or rotating a uniform magnetic field
within a stationary coil
Constant magnetic field
across the wire
Frequency 50 or 60 Hertz Zero
Direction of flow of
electrons.
Bidirectional Unidirectional
14. DIFFERENCE OF DC AND AC CIRCUITS
14
Power Factor Lies between 0 and 1 Always 1
Polarity It has polarity (+, -) Do not have polarity
Obtained From Alternators Generators, battery, solar cell, etc.
Type of load Their load is resistive, inductive or capacitive. Their load is usually resistive in
nature.
Graphical Representation It is represented by irregular waves like triangular
wave, square wave, square tooth wave, sine wave.
It is represented by the straight
line.
Transmission Can be transmitted over long distance with some
losses.
It can be transmitted over very long
distance with negligible losses.
Convertible Easily convert into direct current Easily convert into alternating
current
Substation Few substation is required for generation and
transmission
More substations are required for
generation and transmission
Passive Parameter Impedance Resistance
Harazdous Dangerous Very dangerous
Application Factories, Industries and for the domestic purposes. Electroplating, Electrolysis,
Electronic Equipment etc.
16. ACTIVE COMPONENTS
16
▰ Active components require a source of energy, typically in
the form of a direct current, in order to perform their
specific function. They are able to manipulate the flow of
electricity in some way. Most active components consist
of semiconductor devices, such as diodes, transistors
and integrated circuits.
17. ACTIVE COMPONENTS
17
▰ Transistor: Mostly used for amplifying electrical signals or as switching
devices
▰ Diode: Permits electricity to flow in one direction only
▰ Integrated circuit (chips or microchips): multiple complex circuits on a
circuit board; used to perform all kinds of tasks; still considered a
component despite consisting of many other components
▰ Display devices such as LCD, LED and CRT displays
▰ Power sources such as batteries and other sources of alternating
current (AC) or direct current (DC)
18. PASSIVE COMPONENTS
18
▰ Passive components can influence the flow of electricity
running through them. For example, they can resist its
flow, store energy for later use, or produce inductance.
However, they cannot control or amplify electricity
themselves.
19. PASSIVE COMPONENTS
19
The most common components and their functions:
•Resistor: Resists the flow of electrical current in a circuit; used to lower
voltage
•Capacitor: Stores electrical energy electrostatically in an electric field
(known as ‘charging’), and can release it later when needed
•Inductor: Stores electrical energy in a magnetic field; allows direct current
(DC) to flow through it, but not alternating current (AC)
•Transducer: Converts an input signal from one type of energy into
another type; sensors are a type of transducer that convert physical
action/input into an electrical signal
