4. • A power inverter, or inverter, is an electronic device or
circuitry that changes direct current (DC) to alternating
current (AC).
• The input voltage, output voltage and frequency, and
overall power handling depend on the design of the
specific device or circuitry. The inverter does not
produce any power; the power is provided by the DC
source.
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5. A Transformer is a static electromagnetic device, which
transform an electrical energy from one circuit to another
circuit without change in frequency.
It plays an important role in electronics equipment. AC and
DC voltage in power supply equipment are all most
achieved by transformer’s transformation and
commutation.
Basically a Transformer changes electricity from high to
low voltage using two properties of electricity.
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6. When Transformer is use to “decrease” the
voltage on the secondary winding with respect
to the primary it is called a step – down
Transformer.
When a Transformer is used to “increase’’ the
voltage on its secondary winding with respect to
the primary, it is called a step – up Transformer.
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7. • A rechargeable battery, storage battery is a type of
electrical battery. It compromises one or more
electrochemical cell and is a type of energy accumulator
used for electrochemical energy storage. It is technically
known as a secondary cell because its electrochemical
reactions are electrically reversible. Rechargeable batteries
come in many different shapes and sizes, ranging from
button cell to megawatt system connected to stabilize an
electrical distribution network. Several different
combinations of chemicals are commonly used, including:
lead acid, nickel cadmium, nickel metal hydride, lithium
ion and lithium ion polymer.
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8. A switch mode power supply (SWITCHING-MODE
POWER SUPPLY, SMPS, OR SWITCHER) is an electronic
power supply that incorporates a switching regulator to
convert electrical power efficiently. Like other power
supplies, an SMPS transfers power from a source, like
mains power, to a load, such as a personal computer, while
converting voltage and current characteristic.
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9. A resistor is a passive two- terminal electrical
component that implements electrical resistance as a
circuit element. Resistors act to reduce current flow,
and at the same time, act to lower voltage levels within
circuit. Resistors may have fixed resistances.
The current through a resistor is in direct
proportion to the voltage across the resistor terminals.
This relationship is represented by ohm’s law:
I=V/R
Where I is the current in amperes, V is the potential difference
measured across the conductor in volts, and R is the resistance
of the conductor in ohms.
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11. A capacitor is a passive two terminal electrical
component used to store energy electrostatically in an
electric field. The forms of practical capacitors vary
widely, but all content at least two plates separated by
dielectric medium.
A dielectric can be GLASS, AIR, PAPER, MICA,
ETC. The dielectric acts to increase the capacitor’s
charge capacity. Capacitors are widely used as parts of
electrical circuit in many common electrical devices.
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12. Unlike a resistor, a capacitor does not dissipate energy.
Instead, a capacitor stores energy in the form of an
electrostatic field between its plates.
CAPACITORS
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13. An LED lamp is a light-emitting diode product that
is assembled into a lamp for use in lighting fixtures.
Like incandescent lamp and unlike most
fluorescent lamps (e.g. tube and compact fluorescent
lamp (CFL), LED lights come to full brightness without
need for a warm-up time; the life of fluorescent lighting
is also reduce by frequent switching on and off.
LED chips need controlled direct current (DC)
electrical power; an appropriate power supply is
needed.
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16. • The circuit can be divided into three parts:
oscillator, amplifier and transformer. A 50Hz oscillator is
required as the frequency of AC supply is 50Hz.
• This can be achieved by constructing an A stable
multivibrator which produces a square wave at 50Hz. In
the circuit, R1, R2, R3, R4, C1, C2, T2 and T3 form the
oscillator.
• Each transistor produces inverting square waves.
The values of R1, R2 and C1 (R4, R3 and C2 are identical)
will decide the frequency. The formula for the frequency of
square wave generated by the a stable multivibrator is
F = 1/(1.38*R2*C1)
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17. The inverting signals from the oscillator are amplified
by the Power MOSFETS T1 and T4. These amplified
signals are given to the step-up transformer with its
center tap connected to 12V DC.
The turns ratio of the transformer must be 1:19 in order
to convert 12V to 220V. The transformer combines both
the inverting signals to generate a 220V alternating
square wave output.
By using a 24V battery, loads up to 85W can be
powered, but the design is inefficient. In order to
increase the capacity of the inverter, the number of
MOSFETS must be increased.
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18. An inverter is used to produce an un-interrupted 220V
AC (depending on the line voltage of the particular
country) supply to the device connected as the load at
the output socket.
The inverter gives constant AC voltage at its output
socket when the AC mains power supply is not
available.
The 100 watt inverter applicable for home application
and light load.
AC can’t be stored for feature use whereas DC can be
store in battery & it can be converted back to AC by
using power inverters when require.
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