Transistors are key components of inverters that convert DC power from sources like batteries into AC power. Transistors rapidly switch on and off when connected to a transformer, which allows direct current to be converted into alternating current. There are three main types of inverters - square wave inverters, which output a basic alternating signal but not a pure sine wave; modified sine wave inverters, which have brief pauses between phase shifts; and pure sine wave inverters, which have the most complex circuitry to accurately produce a sine wave output. Inverters have applications in devices like uninterruptible power supplies, electronic ballasts, and variable frequency drives.

1. TOPIC - TYPES AND
WORKING PRINCIPLE
OF INVERTERS
LAB @ HOME

2. CONTENTS :
INTRODUCTION
WORKING PRINCIPLE
TYPES OF INVERTERS
APPLICATIONS
ACTIVITY

3. AN INVERTER IS AN
ELECTRICAL CIRCUIT
CAPABLE OF TURNING
DC POWER INTO AC
POWER , WHILE AT
THE SAME TIME
REGULATING THE
VOLTAGE , CURRENT
AND FREQUENCY OF
THE SIGNAL .

4. Transistors are key componentsof power inverters, whichconvert direct
current (DC) to alternating current (AC) power. The transistor is usedto
change the steady voltage and one-way current flowof DC to the
constantly changing voltage and oscillatingcurrent of AC . Transistors are
usedas switches to control electrical flowthrougha circuit. The key feature of
the transistor in the generation of AC power is that it can be rapidly switched
on and off. A pair (or more) of transistors are used in tandemwitha
transformer to make the conversion. Direct current power is fedinto
transistors on bothsides of a transformer input, and those transistors are
alternately switched on and off, whichcreates alternating current.

5. CIRCUIT DIAGRAM

6. i . THE SQUARE WAVE INVERTER :
A square wave inverter is one of the simplest inverter types , which convert a straight
DC signal to a phase shifting AC signal . But the output is not pure AC , i.e. in the
formof a pure sine wave, but it is a square wave. At the same time they are cheaper
as well . The simplest construction of a square wave inverter can be achievedby using
an on-off switch, before a typical voltage amplifying circuitry like that of a
transformer

7. ii . THE MODIFIED SINE WAVE INVERTER :
A Modified sine wave shows some pauses before the phase shifting of the wave , i.e.
unlike a square it does not shift its phase abruptly frompositive to negative , or unlike
a sine wave, does not make a smooth transition frompositive to negative but takes
brief pauses and then shifts its phase.
iii . A PURE SINE WAVE INVERTER :
The electrical circuit of a pure sine wave inverter is far more complex than a square
wave or modifiedsine wave inverter . Another way to obtain a sine output is to
obtain a square wave output froma square wave inverter and then modify this
output to achieve a pure sine wave

8. APPLICATIONS
FUEL CELLS
UNINTERRUPTIBLE POWER SUPPLIES
ELECTRONIC BALLASTS & INDUCTION
HEATERS
VARIABLE - FREQUENCY DRIVES
HVDC POWER TRANSMISSION
WIND TURBINES & MICROTURBINES

9. ACTIVITY
WORKING OF POWER GENERATOR